implement PR2328.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@51176 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp
index 2f4b1926d8c04f8c4a4b69774bb05201f1a0ab18..0f9df27fa46b4216d5cc7d9a78215de5301eaa35 100644 (file)
--- a/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/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/test/Transforms/InstCombine/div.ll b/test/Transforms/InstCombine/div.ll
index b21d39b7a539e6014bfaebd9d4ee5a6190eec1f5..ea6ea6323c5645768f4612dd0980993c81f2ac44 100644 (file)
--- a/test/Transforms/InstCombine/div.ll
+++ b/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             ; <i32> [#uses=1]
@@ -72,3 +70,15 @@ define i32 @test11(i32 %X, i1 %C) {
         %B = udiv i32 %X, %A            ; <i32> [#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
+}
+