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Fix X86FastISel's address folding to check displacement

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values for overflow.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@56686 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dan Gohman 2008-09-26 20:04:15 +00:00
parent 36a55023c1
commit 09aae469ce
1 changed files with 12 additions and 5 deletions

17
lib/Target/X86/X86FastISel.cpp

@ -345,8 +345,12 @@ bool X86FastISel::X86SelectAddress(Value *V, X86AddressMode &AM, bool isCall) {
if (isCall) break;
// Adds of constants are common and easy enough.
if (ConstantInt *CI = dyn_cast<ConstantInt>(U->getOperand(1))) {
AM.Disp += CI->getZExtValue();
return X86SelectAddress(U->getOperand(0), AM, isCall);
uint64_t Disp = (int32_t)AM.Disp + (uint64_t)CI->getSExtValue();
// They have to fit in the 32-bit signed displacement field though.
if (isInt32(Disp)) {
AM.Disp = (uint32_t)Disp;
return X86SelectAddress(U->getOperand(0), AM, isCall);
}
}
break;
}
@ -354,7 +358,7 @@ bool X86FastISel::X86SelectAddress(Value *V, X86AddressMode &AM, bool isCall) {
case Instruction::GetElementPtr: {
if (isCall) break;
// Pattern-match simple GEPs.
uint64_t Disp = AM.Disp;
uint64_t Disp = (int32_t)AM.Disp;
unsigned IndexReg = AM.IndexReg;
unsigned Scale = AM.Scale;
gep_type_iterator GTI = gep_type_begin(U);
@ -371,7 +375,7 @@ bool X86FastISel::X86SelectAddress(Value *V, X86AddressMode &AM, bool isCall) {
uint64_t S = TD.getABITypeSize(GTI.getIndexedType());
if (ConstantInt *CI = dyn_cast<ConstantInt>(Op)) {
// Constant-offset addressing.
Disp += CI->getZExtValue() * S;
Disp += CI->getSExtValue() * S;
} else if (IndexReg == 0 &&
(!AM.GV ||
!getTargetMachine()->symbolicAddressesAreRIPRel()) &&
@ -386,11 +390,14 @@ bool X86FastISel::X86SelectAddress(Value *V, X86AddressMode &AM, bool isCall) {
goto unsupported_gep;
}
}
// Check for displacement overflow.
if (!isInt32(Disp))
break;
// Ok, the GEP indices were covered by constant-offset and scaled-index
// addressing. Update the address state and move on to examining the base.
AM.IndexReg = IndexReg;
AM.Scale = Scale;
AM.Disp = Disp;
AM.Disp = (uint32_t)Disp;
return X86SelectAddress(U->getOperand(0), AM, isCall);
unsupported_gep:
// Ok, the GEP indices weren't all covered.