f65ddc5fa2
JumpThreading iterates over F until the IR quiesces. Transforming unreachable BBs increases compile time and it is also possible to never stabilize causing JumpThreading to hang. An older attempt at fixing this problem was D3991 where removeUnreachableBlocks(F) was called before JumpThreading began. This has a few drawbacks: * expensive - the routine attempts to fix up the IR to identify additional BBs that can be removed along with unreachable BBs. * aggressive - does not identify and preserve the shape of the IR. At a minimum it does not preserve loop hierarchies. * invasive - altering reachable blocks it may disrupt IR shapes that could have otherwise been JumpThreaded. This patch avoids removeUnreachableBlocks(F) and instead tracks unreachable BBs in a SmallPtrSet using DominatorTree to validate the initial state of all BBs. We then rely on subsequent passes to identify and remove these unreachable blocks from F. Reviewers: dberlin, sebpop, kuhar, dinesh.d Reviewed by: sebpop, kuhar Subscribers: hiraditya, uabelho, llvm-commits Differential Revision: https://reviews.llvm.org/D44177 llvm-svn: 327713
366 lines
11 KiB
LLVM
366 lines
11 KiB
LLVM
; RUN: opt -S -jump-threading < %s | FileCheck %s
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declare void @foo()
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declare void @bar()
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declare void @baz()
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declare void @quux()
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; Jump threading of branch with select as condition.
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; Mostly theoretical since instruction combining simplifies all selects of
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; booleans where at least one operand is true/false/undef.
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; CHECK-LABEL: @test_br(
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; CHECK-NEXT: entry:
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; CHECK-NEXT: br i1 %cond, label %L1,
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define void @test_br(i1 %cond, i1 %value) nounwind {
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entry:
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br i1 %cond, label %L0, label %L3
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L0:
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%expr = select i1 %cond, i1 true, i1 %value
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br i1 %expr, label %L1, label %L2
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L1:
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call void @foo()
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ret void
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L2:
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call void @bar()
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ret void
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L3:
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call void @baz()
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br label %L0
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}
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; Jump threading of switch with select as condition.
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; CHECK-LABEL: @test_switch(
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; CHECK-NEXT: entry:
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; CHECK-NEXT: br i1 %cond, label %L1,
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define void @test_switch(i1 %cond, i8 %value) nounwind {
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entry:
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br i1 %cond, label %L0, label %L4
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L0:
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%expr = select i1 %cond, i8 1, i8 %value
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switch i8 %expr, label %L3 [i8 1, label %L1 i8 2, label %L2]
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L1:
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call void @foo()
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ret void
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L2:
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call void @bar()
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ret void
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L3:
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call void @baz()
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ret void
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L4:
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call void @quux()
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br label %L0
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}
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; Make sure the blocks in the indirectbr test aren't trivially removable as
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; successors by taking their addresses.
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@anchor = constant [3 x i8*] [
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i8* blockaddress(@test_indirectbr, %L1),
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i8* blockaddress(@test_indirectbr, %L2),
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i8* blockaddress(@test_indirectbr, %L3)
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]
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; Jump threading of indirectbr with select as address.
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; CHECK-LABEL: @test_indirectbr(
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; CHECK-NEXT: entry:
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; CHECK-NEXT: br i1 %cond, label %L1, label %L3
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define void @test_indirectbr(i1 %cond, i8* %address) nounwind {
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entry:
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br i1 %cond, label %L0, label %L3
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L0:
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%indirect.goto.dest = select i1 %cond, i8* blockaddress(@test_indirectbr, %L1), i8* %address
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indirectbr i8* %indirect.goto.dest, [label %L1, label %L2, label %L3]
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L1:
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call void @foo()
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ret void
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L2:
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call void @bar()
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ret void
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L3:
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call void @baz()
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ret void
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}
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; Jump threading of indirectbr with select as address. Test increased
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; duplication threshold for cases where indirectbr is being threaded
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; through.
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; CHECK-LABEL: @test_indirectbr_thresh(
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; CHECK-NEXT: entry:
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; CHECK-NEXT: br i1 %cond, label %L1, label %L3
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; CHECK-NOT: indirectbr
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define void @test_indirectbr_thresh(i1 %cond, i8* %address) nounwind {
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entry:
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br i1 %cond, label %L0, label %L3
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L0:
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%indirect.goto.dest = select i1 %cond, i8* blockaddress(@test_indirectbr_thresh, %L1), i8* %address
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call void @quux()
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call void @quux()
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call void @quux()
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indirectbr i8* %indirect.goto.dest, [label %L1, label %L2, label %L3]
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L1:
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call void @foo()
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ret void
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L2:
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call void @bar()
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ret void
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L3:
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call void @baz()
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ret void
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}
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; A more complicated case: the condition is a select based on a comparison.
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; CHECK-LABEL: @test_switch_cmp(
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; CHECK-NEXT: entry:
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; CHECK-NEXT: br i1 %cond, label %L0, label %[[THREADED:[A-Za-z.0-9]+]]
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; CHECK: [[THREADED]]:
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; CHECK-NEXT: call void @quux
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; CHECK-NEXT: br label %L1
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define void @test_switch_cmp(i1 %cond, i32 %val, i8 %value) nounwind {
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entry:
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br i1 %cond, label %L0, label %L4
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L0:
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%val.phi = phi i32 [%val, %entry], [-1, %L4]
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%cmp = icmp slt i32 %val.phi, 0
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%expr = select i1 %cmp, i8 1, i8 %value
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switch i8 %expr, label %L3 [i8 1, label %L1 i8 2, label %L2]
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L1:
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call void @foo()
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ret void
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L2:
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call void @bar()
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ret void
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L3:
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call void @baz()
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ret void
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L4:
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call void @quux()
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br label %L0
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}
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; Make sure the edge value of %0 from entry to L2 includes 0 and L3 is
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; reachable.
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; CHECK: test_switch_default
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; CHECK: entry:
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; CHECK: load
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; CHECK: switch
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; CHECK: [[THREADED:[A-Za-z.0-9]+]]:
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; CHECK: store
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; CHECK: br
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; CHECK: L2:
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; CHECK-SAME: preds = %entry, %entry
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; CHECK-NEXT: phi i32
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define void @test_switch_default(i32* nocapture %status) nounwind {
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entry:
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%0 = load i32, i32* %status, align 4
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switch i32 %0, label %L2 [
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i32 5061, label %L1
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i32 0, label %L2
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]
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L1:
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store i32 10025, i32* %status, align 4
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br label %L2
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L2:
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%1 = load i32, i32* %status, align 4
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%cmp57.i = icmp eq i32 %1, 0
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br i1 %cmp57.i, label %L3, label %L4
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L3:
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store i32 10000, i32* %status, align 4
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br label %L4
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L4:
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ret void
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}
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define void @unfold1(double %x, double %y) nounwind {
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entry:
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%sub = fsub double %x, %y
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%cmp = fcmp ogt double %sub, 1.000000e+01
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br i1 %cmp, label %cond.end4, label %cond.false
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cond.false: ; preds = %entry
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%add = fadd double %x, %y
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%cmp1 = fcmp ogt double %add, 1.000000e+01
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%add. = select i1 %cmp1, double %add, double 0.000000e+00
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br label %cond.end4
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cond.end4: ; preds = %entry, %cond.false
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%cond5 = phi double [ %add., %cond.false ], [ %sub, %entry ]
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%cmp6 = fcmp oeq double %cond5, 0.000000e+00
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br i1 %cmp6, label %if.then, label %if.end
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if.then: ; preds = %cond.end4
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call void @foo()
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br label %if.end
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if.end: ; preds = %if.then, %cond.end4
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ret void
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; CHECK-LABEL: @unfold1
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; CHECK: br i1 %cmp, label %cond.end4, label %cond.false
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; CHECK: br i1 %cmp1, label %cond.end4, label %if.then
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; CHECK: br i1 %cmp6, label %if.then, label %if.end
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; CHECK: br label %if.end
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}
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define void @unfold2(i32 %x, i32 %y) nounwind {
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entry:
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%sub = sub nsw i32 %x, %y
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%cmp = icmp sgt i32 %sub, 10
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br i1 %cmp, label %cond.end4, label %cond.false
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cond.false: ; preds = %entry
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%add = add nsw i32 %x, %y
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%cmp1 = icmp sgt i32 %add, 10
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%add. = select i1 %cmp1, i32 0, i32 %add
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br label %cond.end4
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cond.end4: ; preds = %entry, %cond.false
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%cond5 = phi i32 [ %add., %cond.false ], [ %sub, %entry ]
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%cmp6 = icmp eq i32 %cond5, 0
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br i1 %cmp6, label %if.then, label %if.end
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if.then: ; preds = %cond.end4
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call void @foo()
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br label %if.end
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if.end: ; preds = %if.then, %cond.end4
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ret void
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; CHECK-LABEL: @unfold2
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; CHECK: br i1 %cmp, label %if.end, label %cond.false
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; CHECK: br i1 %cmp1, label %if.then, label %cond.end4
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; CHECK: br i1 %cmp6, label %if.then, label %if.end
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; CHECK: br label %if.end
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}
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define i32 @unfold3(i32 %u, i32 %v, i32 %w, i32 %x, i32 %y, i32 %z, i32 %j) nounwind {
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entry:
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%add3 = add nsw i32 %j, 2
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%cmp.i = icmp slt i32 %u, %v
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br i1 %cmp.i, label %.exit, label %cond.false.i
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cond.false.i: ; preds = %entry
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%cmp4.i = icmp sgt i32 %u, %v
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br i1 %cmp4.i, label %.exit, label %cond.false.6.i
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cond.false.6.i: ; preds = %cond.false.i
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%cmp8.i = icmp slt i32 %w, %x
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br i1 %cmp8.i, label %.exit, label %cond.false.10.i
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cond.false.10.i: ; preds = %cond.false.6.i
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%cmp13.i = icmp sgt i32 %w, %x
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br i1 %cmp13.i, label %.exit, label %cond.false.15.i
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cond.false.15.i: ; preds = %cond.false.10.i
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%phitmp = icmp sge i32 %y, %z
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br label %.exit
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.exit: ; preds = %entry, %cond.false.i, %cond.false.6.i, %cond.false.10.i, %cond.false.15.i
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%cond23.i = phi i1 [ false, %entry ], [ true, %cond.false.i ], [ false, %cond.false.6.i ], [ %phitmp, %cond.false.15.i ], [ true, %cond.false.10.i ]
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%j.add3 = select i1 %cond23.i, i32 %j, i32 %add3
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ret i32 %j.add3
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; CHECK-LABEL: @unfold3
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; CHECK: br i1 %cmp.i, label %.exit.thread2, label %cond.false.i
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; CHECK: br i1 %cmp4.i, label %.exit.thread, label %cond.false.6.i
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; CHECK: br i1 %cmp8.i, label %.exit.thread2, label %cond.false.10.i
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; CHECK: br i1 %cmp13.i, label %.exit.thread, label %.exit
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; CHECK: br i1 %phitmp, label %.exit.thread, label %.exit.thread2
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; CHECK: br label %.exit.thread2
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}
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define i32 @unfold4(i32 %u, i32 %v, i32 %w, i32 %x, i32 %y, i32 %z, i32 %j) nounwind {
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entry:
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%add3 = add nsw i32 %j, 2
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%cmp.i = icmp slt i32 %u, %v
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br i1 %cmp.i, label %.exit, label %cond.false.i
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cond.false.i: ; preds = %entry
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%cmp4.i = icmp sgt i32 %u, %v
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br i1 %cmp4.i, label %.exit, label %cond.false.6.i
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cond.false.6.i: ; preds = %cond.false.i
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%cmp8.i = icmp slt i32 %w, %x
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br i1 %cmp8.i, label %.exit, label %cond.false.10.i
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cond.false.10.i: ; preds = %cond.false.6.i
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%cmp13.i = icmp sgt i32 %w, %x
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br i1 %cmp13.i, label %.exit, label %cond.false.15.i
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cond.false.15.i: ; preds = %cond.false.10.i
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%cmp19.i = icmp sge i32 %y, %z
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%conv = zext i1 %cmp19.i to i32
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br label %.exit
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.exit: ; preds = %entry, %cond.false.i, %cond.false.6.i, %cond.false.10.i, %cond.false.15.i
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%cond23.i = phi i32 [ 1, %entry ], [ 0, %cond.false.i ], [ 1, %cond.false.6.i ], [ %conv, %cond.false.15.i ], [ 0, %cond.false.10.i ]
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%lnot.i18 = icmp eq i32 %cond23.i, 1
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%j.add3 = select i1 %lnot.i18, i32 %j, i32 %add3
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ret i32 %j.add3
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; CHECK-LABEL: @unfold4
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; CHECK: br i1 %cmp.i, label %.exit.thread, label %cond.false.i
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; CHECK: br i1 %cmp4.i, label %.exit.thread3, label %cond.false.6.i
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; CHECK: br i1 %cmp8.i, label %.exit.thread, label %cond.false.10.i
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; CHECK: br i1 %cmp13.i, label %.exit.thread3, label %.exit
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; CHECK: br i1 %lnot.i18, label %.exit.thread, label %.exit.thread3
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; CHECK: br label %.exit.thread3
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}
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define i32 @unfold5(i32 %u, i32 %v, i32 %w, i32 %x, i32 %y, i32 %z, i32 %j) nounwind {
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entry:
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%add3 = add nsw i32 %j, 2
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%cmp.i = icmp slt i32 %u, %v
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br i1 %cmp.i, label %.exit, label %cond.false.i
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cond.false.i: ; preds = %entry
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%cmp4.i = icmp sgt i32 %u, %v
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br i1 %cmp4.i, label %.exit, label %cond.false.6.i
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cond.false.6.i: ; preds = %cond.false.i
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%cmp8.i = icmp slt i32 %w, %x
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br i1 %cmp8.i, label %.exit, label %cond.false.10.i
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cond.false.10.i: ; preds = %cond.false.6.i
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%cmp13.i = icmp sgt i32 %w, %x
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br i1 %cmp13.i, label %.exit, label %cond.false.15.i
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cond.false.15.i: ; preds = %cond.false.10.i
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%cmp19.i = icmp sge i32 %y, %z
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%conv = zext i1 %cmp19.i to i32
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br label %.exit
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.exit: ; preds = %entry, %cond.false.i, %cond.false.6.i, %cond.false.10.i, %cond.false.15.i
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%cond23.i = phi i32 [ 2, %entry ], [ 3, %cond.false.i ], [ 1, %cond.false.6.i ], [ %conv, %cond.false.15.i ], [ 7, %cond.false.10.i ]
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%lnot.i18 = icmp sgt i32 %cond23.i, 5
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%j.add3 = select i1 %lnot.i18, i32 %j, i32 %cond23.i
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ret i32 %j.add3
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; CHECK-LABEL: @unfold5
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; CHECK: br i1 %cmp.i, label %.exit, label %cond.false.i
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; CHECK: br i1 %cmp4.i, label %.exit, label %cond.false.6.i
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; CHECK: br i1 %cmp8.i, label %.exit, label %cond.false.10.i
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; CHECK: br i1 %cmp13.i, label %.exit, label %cond.false.15.i
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; CHECK: br label %.exit
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}
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