Calculate __builtin_object_size when pointer depends on a condition
This patch fixes calculating of builtin_object_size if it depends on a
condition. Before this patch compiler did not know how to calculate the
object size when it finds a condition that cannot be eliminated.
This patch enables calculating of builtin_object_size even in case when
condition cannot be eliminated by choosing minimum or maximum value as a
result from condition. Choosing minimum or maximum value from condition
is based on the second argument of __builtin_object_size function.
Patch by Strahinja Petrovic.
Differential Revision: http://reviews.llvm.org/D18438
llvm-svn: 266193
diff --git a/llvm/lib/CodeGen/CodeGenPrepare.cpp b/llvm/lib/CodeGen/CodeGenPrepare.cpp
index e9e6146..ea1325a 100644
--- a/llvm/lib/CodeGen/CodeGenPrepare.cpp
+++ b/llvm/lib/CodeGen/CodeGenPrepare.cpp
@@ -22,6 +22,7 @@
#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/Analysis/ValueTracking.h"
+#include "llvm/Analysis/MemoryBuiltins.h"
#include "llvm/IR/CallSite.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DataLayout.h"
@@ -1807,10 +1808,18 @@
default: break;
case Intrinsic::objectsize: {
// Lower all uses of llvm.objectsize.*
- bool Min = (cast<ConstantInt>(II->getArgOperand(1))->getZExtValue() == 1);
+ uint64_t Size;
Type *ReturnTy = CI->getType();
- Constant *RetVal = ConstantInt::get(ReturnTy, Min ? 0 : -1ULL);
-
+ Constant *RetVal = nullptr;
+ ConstantInt *Op1 = cast<ConstantInt>(II->getArgOperand(1));
+ ObjSizeMode Mode = Op1->isZero() ? ObjSizeMode::Max : ObjSizeMode::Min;
+ if (getObjectSize(II->getArgOperand(0),
+ Size, *DL, TLInfo, false, Mode)) {
+ RetVal = ConstantInt::get(ReturnTy, Size);
+ } else {
+ RetVal = ConstantInt::get(ReturnTy,
+ Mode == ObjSizeMode::Min ? 0 : -1ULL);
+ }
// Substituting this can cause recursive simplifications, which can
// invalidate our iterator. Use a WeakVH to hold onto it in case this
// happens.