[llvm-commits] [llvm] r45403 - in /llvm/trunk/lib/Transforms/Scalar: InstructionCombining.cpp SCCP.cpp
Christopher Lamb
christopher.lamb at gmail.com
Fri Dec 28 23:56:53 PST 2007
Author: clamb
Date: Sat Dec 29 01:56:53 2007
New Revision: 45403
URL: http://llvm.org/viewvc/llvm-project?rev=45403&view=rev
Log:
Disable null pointer folding transforms for non-generic address spaces. This should probably be a target-specific predicate based on address space. That way for targets where this isn't applicable the predicate can be optimized away.
Modified:
llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp
llvm/trunk/lib/Transforms/Scalar/SCCP.cpp
Modified: llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp?rev=45403&r1=45402&r2=45403&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp Sat Dec 29 01:56:53 2007
@@ -9338,8 +9338,11 @@
return ReplaceInstUsesWith(LI, LIB);
}
- if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(Op))
- if (isa<ConstantPointerNull>(GEPI->getOperand(0))) {
+ if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(Op)) {
+ const Value *GEPI0 = GEPI->getOperand(0);
+ // TODO: Consider a target hook for valid address spaces for this xform.
+ if (isa<ConstantPointerNull>(GEPI0) &&
+ cast<PointerType>(GEPI0->getType())->getAddressSpace() == 0) {
// Insert a new store to null instruction before the load to indicate
// that this code is not reachable. We do this instead of inserting
// an unreachable instruction directly because we cannot modify the
@@ -9348,10 +9351,13 @@
Constant::getNullValue(Op->getType()), &LI);
return ReplaceInstUsesWith(LI, UndefValue::get(LI.getType()));
}
+ }
if (Constant *C = dyn_cast<Constant>(Op)) {
// load null/undef -> undef
- if ((C->isNullValue() || isa<UndefValue>(C))) {
+ // TODO: Consider a target hook for valid address spaces for this xform.
+ if (isa<UndefValue>(C) || (C->isNullValue() &&
+ cast<PointerType>(Op->getType())->getAddressSpace() == 0)) {
// Insert a new store to null instruction before the load to indicate that
// this code is not reachable. We do this instead of inserting an
// unreachable instruction directly because we cannot modify the CFG.
Modified: llvm/trunk/lib/Transforms/Scalar/SCCP.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/SCCP.cpp?rev=45403&r1=45402&r2=45403&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/SCCP.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/SCCP.cpp Sat Dec 29 01:56:53 2007
@@ -1015,7 +1015,9 @@
if (PtrVal.isUndefined()) return; // The pointer is not resolved yet!
if (PtrVal.isConstant() && !I.isVolatile()) {
Value *Ptr = PtrVal.getConstant();
- if (isa<ConstantPointerNull>(Ptr)) {
+ // TODO: Consider a target hook for valid address spaces for this xform.
+ if (isa<ConstantPointerNull>(Ptr) &&
+ cast<PointerType>(Ptr->getType())->getAddressSpace() == 0) {
// load null -> null
markConstant(IV, &I, Constant::getNullValue(I.getType()));
return;
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