From 5c953b7d27b88649e6279b815a3eba53756bc282 Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Fri, 16 May 2008 02:59:42 +0000 Subject: [PATCH] implement PR2328. llvm-svn: 51176 --- .../lib/Transforms/Scalar/InstructionCombining.cpp | 4 ++++ llvm/test/Transforms/InstCombine/div.ll | 14 ++++++++++++-- 2 files changed, 16 insertions(+), 2 deletions(-) diff --git a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp index 2f4b1926d8c0..0f9df27fa46b 100644 --- a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp @@ -3012,6 +3012,10 @@ Instruction *InstCombiner::commonDivTransforms(BinaryOperator &I) { Instruction *InstCombiner::commonIDivTransforms(BinaryOperator &I) { Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1); + // (sdiv X, X) --> 1 (udiv X, X) --> 1 + if (Op0 == Op1) + return ReplaceInstUsesWith(I, ConstantInt::get(I.getType(), 1)); + if (Instruction *Common = commonDivTransforms(I)) return Common; diff --git a/llvm/test/Transforms/InstCombine/div.ll b/llvm/test/Transforms/InstCombine/div.ll index b21d39b7a539..ea6ea6323c56 100644 --- a/llvm/test/Transforms/InstCombine/div.ll +++ b/llvm/test/Transforms/InstCombine/div.ll @@ -1,8 +1,6 @@ ; This test makes sure that div instructions are properly eliminated. -; ; RUN: llvm-as < %s | opt -instcombine | llvm-dis | not grep div -; END. define i32 @test1(i32 %A) { %B = sdiv i32 %A, 1 ; [#uses=1] @@ -72,3 +70,15 @@ define i32 @test11(i32 %X, i1 %C) { %B = udiv i32 %X, %A ; [#uses=1] ret i32 %B } + +; PR2328 +define i32 @test12(i32 %x) nounwind { + %tmp3 = udiv i32 %x, %x ; 1 + ret i32 %tmp3 +} + +define i32 @test13(i32 %x) nounwind { + %tmp3 = sdiv i32 %x, %x ; 1 + ret i32 %tmp3 +} +