[llvm-commits] [llvm] r97860 - in /llvm/trunk: lib/Transforms/InstCombine/InstCombineCalls.cpp test/Transforms/InstCombine/objsize.ll

[Evan Cheng]

Author: evancheng
Date: Fri Mar  5 19:01:42 2010
New Revision: 97860

URL: http://llvm.org/viewvc/llvm-project?rev=97860&view=rev
Log:
Transform @llvm.objectsize to integer if the argument is a result of malloc of known size.

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=97860&r1=97859&r2=97860&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineCalls.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineCalls.cpp Fri Mar  5 19:01:42 2010
@@ -336,6 +336,16 @@
         }
         return ReplaceInstUsesWith(CI, ConstantInt::get(ReturnTy, AllocaSize));
       }
+    } else if (CallInst *MI = extractMallocCall(Op1)) {
+      const Type* MallocType = getMallocAllocatedType(MI);
+      // Get alloca size.
+      if (MallocType->isSized()) {
+        if (Value *NElems = getMallocArraySize(MI, TD, true)) {
+          if (ConstantInt *NElements = dyn_cast<ConstantInt>(NElems))
+        return ReplaceInstUsesWith(CI, ConstantInt::get(ReturnTy,
+               (NElements->getZExtValue() * TD->getTypeAllocSize(MallocType))));
+        }
+      }
     } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Op1)) {      
       // Only handle constant GEPs here.
       if (CE->getOpcode() != Instruction::GetElementPtr) break;

Modified: llvm/trunk/test/Transforms/InstCombine/objsize.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/objsize.ll?rev=97860&r1=97859&r2=97860&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/objsize.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/objsize.ll Fri Mar  5 19:01:42 2010
@@ -118,8 +118,24 @@
   ret i32 0
 }
 
+ at s = external global i8*
+
+define void @test5(i32 %n) nounwind ssp {
+; CHECK: @test5
+entry:
+  %0 = tail call noalias i8* @malloc(i32 20) nounwind
+  %1 = tail call i32 @llvm.objectsize.i32(i8* %0, i1 false)
+  %2 = load i8** @s, align 8
+; CHECK-NOT: @llvm.objectsize
+; CHECK: @__memcpy_chk(i8* %0, i8* %1, i32 10, i32 20)
+  %3 = tail call i8* @__memcpy_chk(i8* %0, i8* %2, i32 10, i32 %1) nounwind
+  ret void
+}
+
 declare i8* @__memset_chk(i8*, i32, i64, i64) nounwind
 
+declare noalias i8* @malloc(i32) nounwind
+
 declare i32 @llvm.objectsize.i32(i8*, i1) nounwind readonly
 
 declare i64 @llvm.objectsize.i64(i8*, i1) nounwind readonly