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[X86] Make hasNoCarryFlagUses/hasNoSignedComparisonUses take an SDValue that indicates which result is the flag result. NFCI

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hasNoCarryFlagUses hardcoded that the flag result is 1 and used that to filter which uses were of interest. hasNoSignedComparisonUses just assumes the only result is flags and checks whether any user of the node is a CopyToReg instruction.

After this patch we now do a result number check in both and rely on the caller to provide the result number.

This shouldn't change behavior it was just an odd difference between the two functions that I noticed.

llvm-svn: 349222
This commit is contained in:
Craig Topper 2018-12-15 01:07:16 +00:00
parent bd36255223
commit f1d36485d5
1 changed files with 19 additions and 20 deletions
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39
lib/Target/X86/X86ISelDAGToDAG.cpp
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@ -2193,16 +2193,16 @@ bool X86DAGToDAGISel::isSExtAbsoluteSymbolRef(unsigned Width, SDNode *N) const {
/// Test whether the given X86ISD::CMP node has any uses which require the SF
/// or OF bits to be accurate.
static bool hasNoSignedComparisonUses(SDNode *N) {
static bool hasNoSignedComparisonUses(SDValue Flags) {
// Examine each user of the node.
for (SDNode::use_iterator UI = N->use_begin(),
UE = N->use_end(); UI != UE; ++UI) {
// Only examine CopyToReg uses.
if (UI->getOpcode() != ISD::CopyToReg)
return false;
for (SDNode::use_iterator UI = Flags->use_begin(), UE = Flags->use_end();
UI != UE; ++UI) {
// Only check things that use the flags.
if (UI.getUse().getResNo() != Flags.getResNo())
continue;
// Only examine CopyToReg uses that copy to EFLAGS.
if (cast<RegisterSDNode>(UI->getOperand(1))->getReg() !=
X86::EFLAGS)
if (UI->getOpcode() != ISD::CopyToReg ||
cast<RegisterSDNode>(UI->getOperand(1))->getReg() != X86::EFLAGS)
return false;
// Examine each user of the CopyToReg use.
for (SDNode::use_iterator FlagUI = UI->use_begin(),
@ -2255,18 +2255,16 @@ static bool hasNoSignedComparisonUses(SDNode *N) {
/// Test whether the given node which sets flags has any uses which require the
/// CF flag to be accurate.
static bool hasNoCarryFlagUses(SDNode *N) {
static bool hasNoCarryFlagUses(SDValue Flags) {
// Examine each user of the node.
for (SDNode::use_iterator UI = N->use_begin(), UE = N->use_end(); UI != UE;
++UI) {
for (SDNode::use_iterator UI = Flags->use_begin(), UE = Flags->use_end();
UI != UE; ++UI) {
// Only check things that use the flags.
if (UI.getUse().getResNo() != 1)
if (UI.getUse().getResNo() != Flags.getResNo())
continue;
// Only examine CopyToReg uses.
if (UI->getOpcode() != ISD::CopyToReg)
return false;
// Only examine CopyToReg uses that copy to EFLAGS.
if (cast<RegisterSDNode>(UI->getOperand(1))->getReg() != X86::EFLAGS)
if (UI->getOpcode() != ISD::CopyToReg ||
cast<RegisterSDNode>(UI->getOperand(1))->getReg() != X86::EFLAGS)
return false;
// Examine each user of the CopyToReg use.
for (SDNode::use_iterator FlagUI = UI->use_begin(), FlagUE = UI->use_end();
@ -2631,7 +2629,7 @@ bool X86DAGToDAGISel::foldLoadStoreIntoMemOperand(SDNode *Node) {
(-OperandV).getMinSignedBits() <= 8) ||
(MemVT == MVT::i64 && OperandV.getMinSignedBits() > 32 &&
(-OperandV).getMinSignedBits() <= 32)) &&
hasNoCarryFlagUses(StoredVal.getNode())) {
hasNoCarryFlagUses(StoredVal.getValue(1))) {
OperandV = -OperandV;
Opc = Opc == X86ISD::ADD ? X86ISD::SUB : X86ISD::ADD;
}
@ -3717,7 +3715,7 @@ void X86DAGToDAGISel::Select(SDNode *Node) {
if (isUInt<8>(Mask) &&
(!(Mask & 0x80) || CmpVT == MVT::i8 ||
hasNoSignedComparisonUses(Node))) {
hasNoSignedComparisonUses(SDValue(Node, 0)))) {
// For example, convert "testl %eax, $8" to "testb %al, $8"
VT = MVT::i8;
SubRegOp = X86::sub_8bit;
@ -3725,7 +3723,7 @@ void X86DAGToDAGISel::Select(SDNode *Node) {
MOpc = X86::TEST8mi;
} else if (OptForMinSize && isUInt<16>(Mask) &&
(!(Mask & 0x8000) || CmpVT == MVT::i16 ||
hasNoSignedComparisonUses(Node))) {
hasNoSignedComparisonUses(SDValue(Node, 0)))) {
// For example, "testl %eax, $32776" to "testw %ax, $32776".
// NOTE: We only want to form TESTW instructions if optimizing for
// min size. Otherwise we only save one byte and possibly get a length
@ -3739,7 +3737,8 @@ void X86DAGToDAGISel::Select(SDNode *Node) {
// Without minsize 16-bit Cmps can get here so we need to
// be sure we calculate the correct sign flag if needed.
(CmpVT != MVT::i16 || !(Mask & 0x8000))) ||
CmpVT == MVT::i32 || hasNoSignedComparisonUses(Node))) {
CmpVT == MVT::i32 ||
hasNoSignedComparisonUses(SDValue(Node, 0)))) {
// For example, "testq %rax, $268468232" to "testl %eax, $268468232".
// NOTE: We only want to run that transform if N0 is 32 or 64 bits.
// Otherwize, we find ourselves in a position where we have to do