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The 32-bit displacement field in an x86 address is signed. Arrange for it 

to be sign-extended when it is promoted to 64 bits for intermediate
offset calculations. The offset calculations are done as uint64_t so that
overflow conditions are well defined.

This fixes a problem which is currently hidden by the x86 AsmPrinter but
which was exposed by r58917 (which is temporarily reverted).  See PR3027
for details.

llvm-svn: 59044
This commit is contained in:
Dan Gohman 2008-11-11 15:52:29 +00:00
parent 3987b17e28
commit 059c4fa8d8
1 changed files with 13 additions and 10 deletions
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23
llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
View File

@ -66,7 +66,7 @@ namespace {
bool isRIPRel; // RIP as base?
unsigned Scale;
SDValue IndexReg;
unsigned Disp;
int32_t Disp;
GlobalValue *GV;
Constant *CP;
const char *ES;
@ -201,7 +201,7 @@ namespace {
else if (AM.JT != -1)
Disp = CurDAG->getTargetJumpTable(AM.JT, MVT::i32);
else
Disp = getI32Imm(AM.Disp);
Disp = CurDAG->getTargetConstant(AM.Disp, MVT::i32);
}
/// getI8Imm - Return a target constant with the specified value, of type
@ -768,7 +768,7 @@ bool X86DAGToDAGISel::MatchAddress(SDValue N, X86ISelAddressMode &AM,
// RIP relative addressing: %rip + 32-bit displacement!
if (AM.isRIPRel) {
if (!AM.ES && AM.JT != -1 && N.getOpcode() == ISD::Constant) {
int64_t Val = cast<ConstantSDNode>(N)->getSExtValue();
uint64_t Val = cast<ConstantSDNode>(N)->getSExtValue();
if (!is64Bit || isInt32(AM.Disp + Val)) {
AM.Disp += Val;
return false;
@ -780,7 +780,7 @@ bool X86DAGToDAGISel::MatchAddress(SDValue N, X86ISelAddressMode &AM,
switch (N.getOpcode()) {
default: break;
case ISD::Constant: {
int64_t Val = cast<ConstantSDNode>(N)->getSExtValue();
uint64_t Val = cast<ConstantSDNode>(N)->getSExtValue();
if (!is64Bit || isInt32(AM.Disp + Val)) {
AM.Disp += Val;
return false;
@ -804,18 +804,20 @@ bool X86DAGToDAGISel::MatchAddress(SDValue N, X86ISelAddressMode &AM,
{
SDValue N0 = N.getOperand(0);
if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(N0)) {
if (!is64Bit || isInt32(AM.Disp + G->getOffset())) {
uint64_t Offset = G->getOffset();
if (!is64Bit || isInt32(AM.Disp + Offset)) {
GlobalValue *GV = G->getGlobal();
AM.GV = GV;
AM.Disp += G->getOffset();
AM.Disp += Offset;
AM.isRIPRel = TM.symbolicAddressesAreRIPRel();
return false;
}
} else if (ConstantPoolSDNode *CP = dyn_cast<ConstantPoolSDNode>(N0)) {
if (!is64Bit || isInt32(AM.Disp + CP->getOffset())) {
uint64_t Offset = CP->getOffset();
if (!is64Bit || isInt32(AM.Disp + Offset)) {
AM.CP = CP->getConstVal();
AM.Align = CP->getAlignment();
AM.Disp += CP->getOffset();
AM.Disp += Offset;
AM.isRIPRel = TM.symbolicAddressesAreRIPRel();
return false;
}
@ -935,15 +937,16 @@ bool X86DAGToDAGISel::MatchAddress(SDValue N, X86ISelAddressMode &AM,
// Handle "X | C" as "X + C" iff X is known to have C bits clear.
if (ConstantSDNode *CN = dyn_cast<ConstantSDNode>(N.getOperand(1))) {
X86ISelAddressMode Backup = AM;
uint64_t Offset = CN->getSExtValue();
// Start with the LHS as an addr mode.
if (!MatchAddress(N.getOperand(0), AM, false) &&
// Address could not have picked a GV address for the displacement.
AM.GV == NULL &&
// On x86-64, the resultant disp must fit in 32-bits.
(!is64Bit || isInt32(AM.Disp + CN->getSExtValue())) &&
(!is64Bit || isInt32(AM.Disp + Offset)) &&
// Check to see if the LHS & C is zero.
CurDAG->MaskedValueIsZero(N.getOperand(0), CN->getAPIntValue())) {
AM.Disp += CN->getZExtValue();
AM.Disp += Offset;
return false;
}
AM = Backup;