//===---------------------------------------------------------------------===//
-This code can be seen in viterbi:
-
- %64 = call noalias i8* @malloc(i64 %62) nounwind
-...
- %67 = call i64 @llvm.objectsize.i64(i8* %64, i1 false) nounwind
- %68 = call i8* @__memset_chk(i8* %64, i32 0, i64 %62, i64 %67) nounwind
-
-llvm.objectsize.i64 should be taught about malloc/calloc, allowing it to
-fold to %62. This is a security win (overflows of malloc will get caught)
-and also a performance win by exposing more memsets to the optimizer.
-
-This occurs several times in viterbi.
-
-Stuff like this occurs in drystone:
-
- %call5 = call i8* @malloc(i32 48) optsize
- %5 = getelementptr inbounds i8* %call5, i32 16
- %6 = call i32 @llvm.objectsize.i32(i8* %5, i1 false)
-
-We should be able to constant fold that.
-
-//===---------------------------------------------------------------------===//
-
This code (from Benchmarks/Dhrystone/dry.c):
define i32 @Func1(i32, i32) nounwind readnone optsize ssp {
}
}
} else if (CallInst *MI = extractMallocCall(Op1)) {
- // Get alloca size.
+ // Get allocation size.
const Type* MallocType = getMallocAllocatedType(MI);
if (MallocType && MallocType->isSized())
if (Value *NElems = getMallocArraySize(MI, TD, true))
if (ConstantInt *NElements = dyn_cast<ConstantInt>(NElems))
Size = NElements->getZExtValue() * TD->getTypeAllocSize(MallocType);
+
+ // If there is no offset we can just return the size passed to malloc.
+ if (Offset == 0)
+ return ReplaceInstUsesWith(CI, MI->getArgOperand(0));
}
// Do not return "I don't know" here. Later optimization passes could
ret i32 %objsize
}
+define i32 @test8(i32 %x) {
+; CHECK: @test8
+ %alloc = call noalias i8* @malloc(i32 %x) nounwind
+ %objsize = call i32 @llvm.objectsize.i32(i8* %alloc, i1 false) nounwind readonly
+; CHECK-NEXT: ret i32 %x
+ ret i32 %objsize
+}
+
+define i32 @test9(i32 %x) {
+; CHECK: @test9
+ %alloc = call noalias i8* @malloc(i32 %x) nounwind
+ %gep = getelementptr inbounds i8* %alloc, i32 16
+ %objsize = call i32 @llvm.objectsize.i32(i8* %gep, i1 false) nounwind readonly
+; CHECK-NOT: ret i32 %x
+ ret i32 %objsize
+}