diff options
| author | Chris Lattner <sabre@nondot.org> | 2008-01-13 20:59:02 +0000 |
|---|---|---|
| committer | Chris Lattner <sabre@nondot.org> | 2008-01-13 20:59:02 +0000 |
| commit | ee2b7a4530736d311fb3e2eae551e0acdb919354 (patch) | |
| tree | 58a288ca2539ed7d4cc29c698174f25b992b3a76 | |
| parent | 1fac17f2e7dafbbe2619bbd253dd7b957052f5e0 (diff) | |
Fix PR1907, a nasty miscompilation because instcombine didn't
realize that ne & sgt was a signed comparison (it was only
looking at whether the left compare was signed).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45937 91177308-0d34-0410-b5e6-96231b3b80d8
| -rw-r--r-- | lib/Transforms/Scalar/InstructionCombining.cpp | 10 | ||||
| -rw-r--r-- | test/Transforms/InstCombine/2008-01-13-AndCmpCmp.ll | 9 |
2 files changed, 17 insertions, 2 deletions
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp index ea53aec76c..9465a31d29 100644 --- a/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/lib/Transforms/Scalar/InstructionCombining.cpp @@ -3495,8 +3495,14 @@ Instruction *InstCombiner::visitAnd(BinaryOperator &I) { ICmpInst::isSignedPredicate(LHSCC) == ICmpInst::isSignedPredicate(RHSCC))) { // Ensure that the larger constant is on the RHS. - ICmpInst::Predicate GT = ICmpInst::isSignedPredicate(LHSCC) ? - ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT; + ICmpInst::Predicate GT; + if (ICmpInst::isSignedPredicate(LHSCC) || + (ICmpInst::isEquality(LHSCC) && + ICmpInst::isSignedPredicate(RHSCC))) + GT = ICmpInst::ICMP_SGT; + else + GT = ICmpInst::ICMP_UGT; + Constant *Cmp = ConstantExpr::getICmp(GT, LHSCst, RHSCst); ICmpInst *LHS = cast<ICmpInst>(Op0); if (cast<ConstantInt>(Cmp)->getZExtValue()) { diff --git a/test/Transforms/InstCombine/2008-01-13-AndCmpCmp.ll b/test/Transforms/InstCombine/2008-01-13-AndCmpCmp.ll new file mode 100644 index 0000000000..71d5bf762c --- /dev/null +++ b/test/Transforms/InstCombine/2008-01-13-AndCmpCmp.ll @@ -0,0 +1,9 @@ +; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep and +; PR1907 + +define i1 @test(i32 %c84.17) { + %tmp2696 = icmp ne i32 %c84.17, 34 ; <i1> [#uses=2] + %tmp2699 = icmp sgt i32 %c84.17, -1 ; <i1> [#uses=1] + %tmp2703 = and i1 %tmp2696, %tmp2699 ; <i1> [#uses=1] + ret i1 %tmp2703 +} |