[llvm-commits] [llvm] r51176 - in /llvm/trunk: lib/Transforms/Scalar/InstructionCombining.cpp test/Transforms/InstCombine/div.ll

[Chris Lattner]

Author: lattner
Date: Thu May 15 21:59:42 2008
New Revision: 51176

URL: http://llvm.org/viewvc/llvm-project?rev=51176&view=rev
Log:
implement PR2328.

Modified:
    llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp
    llvm/trunk/test/Transforms/InstCombine/div.ll

Modified: llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp?rev=51176&r1=51175&r2=51176&view=diff

==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp Thu May 15 21:59:42 2008
@@ -3012,6 +3012,10 @@
 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;
 

Modified: llvm/trunk/test/Transforms/InstCombine/div.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/div.ll?rev=51176&r1=51175&r2=51176&view=diff

==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/div.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/div.ll Thu May 15 21:59:42 2008
@@ -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 @@
         %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
+}
+