46fb810955
Symbolic execution using PredicateInfo is only done for the ssa.copy intrinsic. It's using two potential sources for building the expression: 1. the Value of the instruction for which the instruction is a copy of, and 2. the Value from the contraint in PredicateInfo It's possible to get into an infinite loop when choosing between these two, as described in PR31613. This patch proposes performing swapping of the two values (i.e. choosing the second one for the expression), if that same second value was chosen before; this breaks the cycle. In the testcases provided, where there is a contradiction between the value from symbolic execution and assume instruction, NewGVN reduces the assume to assume(false). Resolves PR31613. Differential Revision: https://reviews.llvm.org/D110907
142 lines
4.9 KiB
LLVM
142 lines
4.9 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
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; RUN: opt < %s -passes=newgvn -S | FileCheck %s
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; REQUIRES: asserts
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target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
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target triple = "x86_64-grtev4-linux-gnu"
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define hidden void @barrier() align 2 {
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; CHECK-LABEL: @barrier(
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; CHECK-NEXT: entry:
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; CHECK-NEXT: [[CALLG:%.*]] = tail call i64 @g()
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; CHECK-NEXT: [[SEL:%.*]] = select i1 undef, i64 0, i64 [[CALLG]]
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; CHECK-NEXT: [[LOADED:%.*]] = load i64, i64* null, align 8
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; CHECK-NEXT: [[ADD:%.*]] = add i64 [[LOADED]], 1
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; CHECK-NEXT: [[SHR17:%.*]] = lshr i64 [[ADD]], 1
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; CHECK-NEXT: [[SUB:%.*]] = add nsw i64 [[SHR17]], -1
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; CHECK-NEXT: br label [[FIRST:%.*]]
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; CHECK: first:
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; CHECK-NEXT: [[PHI_ONE:%.*]] = phi i64 [ [[SEL]], [[ENTRY:%.*]] ], [ 0, [[FIRST]] ], [ 0, [[THIRD:%.*]] ]
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; CHECK-NEXT: [[CMP_PHI1_SUB:%.*]] = icmp eq i64 [[PHI_ONE]], [[SUB]]
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; CHECK-NEXT: br i1 [[CMP_PHI1_SUB]], label [[SECOND:%.*]], label [[FIRST]]
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; CHECK: second:
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; CHECK-NEXT: br label [[THIRD]]
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; CHECK: third:
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; CHECK-NEXT: br i1 false, label [[SECOND]], label [[FIRST]]
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;
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entry:
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%callg = tail call i64 @g()
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%sel = select i1 undef, i64 0, i64 %callg
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%loaded = load i64, i64* null, align 8
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%add = add i64 %loaded, 1
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%shr17 = lshr i64 %add, 1
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%sub = add nsw i64 %shr17, -1
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br label %first
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first:
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%phi_one = phi i64 [ %sel, %entry ], [ 0, %first ], [ 0, %third ]
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%cmp_phi1_sub = icmp eq i64 %phi_one, %sub
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br i1 %cmp_phi1_sub, label %second, label %first
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second:
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%phi_two = phi i64 [ %inc, %third ], [ %phi_one, %first ]
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br label %third
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third:
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%inc = add i64 %phi_two, 1
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%cmp_inc_sub = icmp eq i64 %inc, %sub
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br i1 %cmp_inc_sub, label %second, label %first
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}
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define hidden void @barrier2() align 2 {
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; CHECK-LABEL: @barrier2(
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; CHECK-NEXT: entry:
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; CHECK-NEXT: [[TMP0:%.*]] = load i64, i64* null, align 8
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; CHECK-NEXT: [[CALL9:%.*]] = tail call i64 @g()
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; CHECK-NEXT: [[REM:%.*]] = select i1 undef, i64 0, i64 [[CALL9]]
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; CHECK-NEXT: [[ADD:%.*]] = add i64 [[TMP0]], 1
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; CHECK-NEXT: [[SHR17:%.*]] = lshr i64 [[ADD]], 1
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; CHECK-NEXT: [[SUB:%.*]] = add nsw i64 [[SHR17]], -1
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; CHECK-NEXT: br label [[MAINLOOP:%.*]]
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; CHECK: second.exit:
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; CHECK-NEXT: br label [[FIRST_EXIT:%.*]]
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; CHECK: first.exit:
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; CHECK-NEXT: br label [[MAINLOOP]]
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; CHECK: mainloop:
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; CHECK-NEXT: [[FIRSTPHI:%.*]] = phi i64 [ [[REM]], [[ENTRY:%.*]] ], [ 0, [[FIRST_EXIT]] ]
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; CHECK-NEXT: [[FIRSTCMP:%.*]] = icmp eq i64 [[FIRSTPHI]], [[SUB]]
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; CHECK-NEXT: br i1 [[FIRSTCMP]], label [[SECOND_PREHEADER:%.*]], label [[FIRST_EXIT]]
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; CHECK: second.preheader:
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; CHECK-NEXT: br label [[INNERLOOP:%.*]]
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; CHECK: innerloop:
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; CHECK-NEXT: br label [[CLEANUP:%.*]]
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; CHECK: cleanup:
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; CHECK-NEXT: br i1 false, label [[INNERLOOP]], label [[SECOND_EXIT:%.*]]
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;
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entry:
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%0 = load i64, i64* null, align 8
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%call9 = tail call i64 @g()
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%rem = select i1 undef, i64 0, i64 %call9
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%add = add i64 %0, 1
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%shr17 = lshr i64 %add, 1
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%sub = add nsw i64 %shr17, -1
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br label %mainloop
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second.exit: ; preds = %cleanup
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br label %first.exit
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first.exit: ; preds = %mainloop, %second.exit
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br label %mainloop
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mainloop: ; preds = %first.exit, %entry
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%firstphi = phi i64 [ %rem, %entry ], [ 0, %first.exit ]
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%firstcmp = icmp eq i64 %firstphi, %sub
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br i1 %firstcmp, label %second.preheader, label %first.exit
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second.preheader: ; preds = %mainloop
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br label %innerloop
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innerloop: ; preds = %cleanup, %second.preheader
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%secondphi = phi i64 [ %inc, %cleanup ], [ %firstphi, %second.preheader ]
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br label %cleanup
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cleanup: ; preds = %innerloop
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%inc = add i64 %secondphi, 1
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%secondcmp = icmp eq i64 %inc, %sub
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br i1 %secondcmp, label %innerloop, label %second.exit
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}
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declare hidden i64 @g() local_unnamed_addr align 2
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define void @barrier3(i64 %arg) {
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; CHECK-LABEL: @barrier3(
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; CHECK-NEXT: entry:
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; CHECK-NEXT: br label [[FIRSTLOOP:%.*]]
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; CHECK: firstloop:
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; CHECK-NEXT: [[PHI1:%.*]] = phi i64 [ [[ARG:%.*]], [[ENTRY:%.*]] ], [ 0, [[FIRSTLOOP]] ]
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; CHECK-NEXT: [[CMP1:%.*]] = icmp eq i64 [[PHI1]], -1
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; CHECK-NEXT: br i1 [[CMP1]], label [[SECONDLOOP:%.*]], label [[FIRSTLOOP]]
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; CHECK: secondloop:
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; CHECK-NEXT: call void @llvm.assume(i1 false)
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; CHECK-NEXT: br label [[SECONDLOOP]]
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;
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entry:
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br label %firstloop
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firstloop:
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%phi1 = phi i64 [ %arg, %entry ], [ 0, %firstloop ]
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%cmp1 = icmp eq i64 %phi1, -1
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br i1 %cmp1, label %secondloop, label %firstloop
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secondloop:
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%phi2 = phi i64 [ %inc, %secondloop ], [ %phi1, %firstloop ]
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%inc = add i64 %phi2, 1
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%cmp2 = icmp eq i64 %inc, -1
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call void @llvm.assume(i1 %cmp2)
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br label %secondloop
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}
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declare void @llvm.assume(i1)
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