8f3d16905d
A backedge-taken count doesn't refer to memory; returning a pointer type is nonsense. So make sure we always return an integer. The obvious way to do this would be to just convert the operands of the icmp to integers, but that doesn't quite work out at the moment: isLoopEntryGuardedByCond currently gets confused by ptrtoint operations. So we perform the ptrtoint conversion late for lt/gt operations. The test changes are mostly innocuous. The most interesting changes are more complex SCEV expressions of the form "(-1 * (ptrtoint i8* %ptr to i64)) + %ptr)". This is expected: we can't fold this to zero because we need to preserve the pointer base. The call to isLoopEntryGuardedByCond in howFarToZero is less precise because of ptrtoint operations; this shows up in the function pr46786_c26_char in ptrtoint.ll. Fixing it here would require more complex refactoring. It should eventually be fixed by future improvements to isImpliedCond. See https://bugs.llvm.org/show_bug.cgi?id=46786 for context. Differential Revision: https://reviews.llvm.org/D103656
139 lines
4.6 KiB
LLVM
139 lines
4.6 KiB
LLVM
; RUN: opt -O3 -S -analyze -scalar-evolution < %s -enable-new-pm=0 | FileCheck %s
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; RUN: opt -passes='default<O3>,print<scalar-evolution>' -S < %s 2>&1 | FileCheck %s
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target datalayout = "e-m:m-p:40:64:64:32-i32:32-i16:16-i8:8-n32"
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;
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; This file contains phase ordering tests for scalar evolution.
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; Test that the standard passes don't obfuscate the IR so scalar evolution can't
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; recognize expressions.
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; CHECK: test1
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; The loop body contains two increments by %div.
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; Make sure that 2*%div is recognizable, and not expressed as a bit mask of %d.
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; CHECK: --> {%p,+,(8 * (%d /u 4))}
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define void @test1(i32 %d, i32* %p) nounwind uwtable ssp {
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entry:
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%div = udiv i32 %d, 4
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br label %for.cond
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for.cond: ; preds = %for.inc, %entry
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%p.addr.0 = phi i32* [ %p, %entry ], [ %add.ptr1, %for.inc ]
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%i.0 = phi i32 [ 0, %entry ], [ %inc, %for.inc ]
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%cmp = icmp ne i32 %i.0, 64
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br i1 %cmp, label %for.body, label %for.end
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for.body: ; preds = %for.cond
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store i32 0, i32* %p.addr.0, align 4
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%add.ptr = getelementptr inbounds i32, i32* %p.addr.0, i32 %div
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store i32 1, i32* %add.ptr, align 4
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%add.ptr1 = getelementptr inbounds i32, i32* %add.ptr, i32 %div
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br label %for.inc
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for.inc: ; preds = %for.body
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%inc = add i32 %i.0, 1
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br label %for.cond
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for.end: ; preds = %for.cond
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ret void
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}
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; CHECK: test1a
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; Same thing as test1, but it is even more tempting to fold 2 * (%d /u 2)
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; CHECK: --> {%p,+,(8 * (%d /u 2))}
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define void @test1a(i32 %d, i32* %p) nounwind uwtable ssp {
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entry:
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%div = udiv i32 %d, 2
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br label %for.cond
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for.cond: ; preds = %for.inc, %entry
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%p.addr.0 = phi i32* [ %p, %entry ], [ %add.ptr1, %for.inc ]
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%i.0 = phi i32 [ 0, %entry ], [ %inc, %for.inc ]
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%cmp = icmp ne i32 %i.0, 64
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br i1 %cmp, label %for.body, label %for.end
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for.body: ; preds = %for.cond
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store i32 0, i32* %p.addr.0, align 4
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%add.ptr = getelementptr inbounds i32, i32* %p.addr.0, i32 %div
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store i32 1, i32* %add.ptr, align 4
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%add.ptr1 = getelementptr inbounds i32, i32* %add.ptr, i32 %div
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br label %for.inc
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for.inc: ; preds = %for.body
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%inc = add i32 %i.0, 1
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br label %for.cond
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for.end: ; preds = %for.cond
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ret void
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}
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@array = weak global [101 x i32] zeroinitializer, align 32 ; <[100 x i32]*> [#uses=1]
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; CHECK: Loop %bb: backedge-taken count is 100
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define void @test_range_ref1a(i32 %x) {
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entry:
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br label %bb
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bb: ; preds = %bb, %entry
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%i.01.0 = phi i32 [ 100, %entry ], [ %tmp4, %bb ] ; <i32> [#uses=2]
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%tmp1 = getelementptr [101 x i32], [101 x i32]* @array, i32 0, i32 %i.01.0 ; <i32*> [#uses=1]
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store i32 %x, i32* %tmp1
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%tmp4 = add i32 %i.01.0, -1 ; <i32> [#uses=2]
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%tmp7 = icmp sgt i32 %tmp4, -1 ; <i1> [#uses=1]
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br i1 %tmp7, label %bb, label %return
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return: ; preds = %bb
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ret void
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}
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define i32 @test_loop_idiom_recogize(i32 %x, i32 %y, i32* %lam, i32* %alp) nounwind {
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bb1.thread:
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br label %bb1
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bb1: ; preds = %bb1, %bb1.thread
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%indvar = phi i32 [ 0, %bb1.thread ], [ %indvar.next, %bb1 ] ; <i32> [#uses=4]
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%i.0.reg2mem.0 = sub i32 255, %indvar ; <i32> [#uses=2]
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%0 = getelementptr i32, i32* %alp, i32 %i.0.reg2mem.0 ; <i32*> [#uses=1]
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%1 = load i32, i32* %0, align 4 ; <i32> [#uses=1]
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%2 = getelementptr i32, i32* %lam, i32 %i.0.reg2mem.0 ; <i32*> [#uses=1]
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store i32 %1, i32* %2, align 4
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%3 = sub i32 254, %indvar ; <i32> [#uses=1]
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%4 = icmp slt i32 %3, 0 ; <i1> [#uses=1]
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%indvar.next = add i32 %indvar, 1 ; <i32> [#uses=1]
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br i1 %4, label %bb2, label %bb1
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bb2: ; preds = %bb1
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%tmp10 = mul i32 %indvar, %x ; <i32> [#uses=1]
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%z.0.reg2mem.0 = add i32 %tmp10, %y ; <i32> [#uses=1]
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%5 = add i32 %z.0.reg2mem.0, %x ; <i32> [#uses=1]
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ret i32 %5
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}
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declare void @use(i1)
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declare void @llvm.experimental.guard(i1, ...)
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; This tests getRangeRef acts as intended with different idx size.
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; CHECK: Loop %loop: Unpredictable max backedge-taken count.
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define void @test_range_ref1(i8 %t) {
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entry:
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%t.ptr = inttoptr i8 %t to i8*
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%p.42 = inttoptr i8 42 to i8*
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%cmp1 = icmp slt i8* %t.ptr, %p.42
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call void(i1, ...) @llvm.experimental.guard(i1 %cmp1) [ "deopt"() ]
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br label %loop
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loop:
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%idx = phi i8* [ %t.ptr, %entry ], [ %snext, %loop ]
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%snext = getelementptr inbounds i8, i8* %idx, i64 1
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%c = icmp slt i8* %idx, %p.42
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call void @use(i1 %c)
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%be = icmp slt i8* %snext, %p.42
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br i1 %be, label %loop, label %exit
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exit:
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ret void
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}
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