From 5c1f17221344fe24f8ba78fdbac7db4f79ded257 Mon Sep 17 00:00:00 2001 From: Eli Friedman Date: Sat, 21 Jun 2008 23:36:13 +0000 Subject: [PATCH] Fix for PR2479: correctly optimize expressions like (a > 13) & (a == 15). See also PR1800, which is about the signed case. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52608 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/Scalar/InstructionCombining.cpp | 3 +-- .../InstCombine/2008-06-21-CompareMiscomp.ll | 11 +++++++++++ 2 files changed, 12 insertions(+), 2 deletions(-) create mode 100644 test/Transforms/InstCombine/2008-06-21-CompareMiscomp.ll diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp index 54e611d2a1e..37637bbe63b 100644 --- a/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/lib/Transforms/Scalar/InstructionCombining.cpp @@ -3691,8 +3691,7 @@ Instruction *InstCombiner::visitAnd(BinaryOperator &I) { case ICmpInst::ICMP_UGT: switch (RHSCC) { default: assert(0 && "Unknown integer condition code!"); - case ICmpInst::ICMP_EQ: // (X u> 13 & X == 15) -> X > 13 - return ReplaceInstUsesWith(I, LHS); + case ICmpInst::ICMP_EQ: // (X u> 13 & X == 15) -> X == 15 case ICmpInst::ICMP_UGT: // (X u> 13 & X u> 15) -> X u> 15 return ReplaceInstUsesWith(I, RHS); case ICmpInst::ICMP_SGT: // (X u> 13 & X s> 15) -> no change diff --git a/test/Transforms/InstCombine/2008-06-21-CompareMiscomp.ll b/test/Transforms/InstCombine/2008-06-21-CompareMiscomp.ll new file mode 100644 index 00000000000..e2d71007848 --- /dev/null +++ b/test/Transforms/InstCombine/2008-06-21-CompareMiscomp.ll @@ -0,0 +1,11 @@ +; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep {icmp eq i32 %In, 15} +; PR2479 +; (See also PR1800.) + +define i1 @test(i32 %In) { + %c1 = icmp ugt i32 %In, 13 + %c2 = icmp eq i32 %In, 15 + %V = and i1 %c1, %c2 + ret i1 %V +} + -- 2.34.1