[llvm-commits] [llvm] r122961 - in /llvm/trunk: lib/Transforms/InstCombine/InstCombineCalls.cpp test/Transforms/InstCombine/objsize.ll

[Benjamin Kramer]

Author: d0k
Date: Thu Jan  6 08:22:52 2011
New Revision: 122961

URL: http://llvm.org/viewvc/llvm-project?rev=122961&view=rev
Log:
InstCombine: Turn _chk functions into the "unsafe" variant if length and max langth are equal.

This happens when we take the (non-constant) length from a malloc.

Modified:
    llvm/trunk/lib/Transforms/InstCombine/InstCombineCalls.cpp
    llvm/trunk/test/Transforms/InstCombine/objsize.ll

Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineCalls.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineCalls.cpp?rev=122961&r1=122960&r2=122961&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineCalls.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineCalls.cpp Thu Jan  6 08:22:52 2011
@@ -722,6 +722,8 @@
     NewInstruction = IC->ReplaceInstUsesWith(*CI, With);
   }
   bool isFoldable(unsigned SizeCIOp, unsigned SizeArgOp, bool isString) const {
+    if (CI->getArgOperand(SizeCIOp) == CI->getArgOperand(SizeArgOp))
+      return true;
     if (ConstantInt *SizeCI =
                            dyn_cast<ConstantInt>(CI->getArgOperand(SizeCIOp))) {
       if (SizeCI->isAllOnesValue())

Modified: llvm/trunk/test/Transforms/InstCombine/objsize.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/objsize.ll?rev=122961&r1=122960&r2=122961&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/objsize.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/objsize.ll Thu Jan  6 08:22:52 2011
@@ -176,3 +176,14 @@
 ; CHECK-NOT: ret i32 %x
   ret i32 %objsize
 }
+
+define i8* @test10(i32 %x) {
+; CHECK: @test10
+  %alloc = call noalias i8* @malloc(i32 %x) nounwind
+  %objsize = call i32 @llvm.objectsize.i32(i8* %alloc, i1 false) nounwind readonly
+  tail call i8* @__memset_chk(i8* %alloc, i32 0, i32 %x, i32 %objsize) nounwind
+; CHECK-NOT: @llvm.objectsize
+; CHECK: @llvm.memset
+  ret i8* %alloc
+; CHECK: ret i8*
+}