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[SystemZ] Extend the use of C(L)GFR

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instcombine prefers to put extended operands first, so this patch
handles that case for C(L)GFR.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@196579 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Richard Sandiford
2013-12-06 09:56:50 +00:00
parent e3a804ba21
commit 8bf51dc72b
3 changed files with 62 additions and 6 deletions
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21
lib/Target/SystemZ/SystemZISelLowering.cpp
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@@ -1207,10 +1207,14 @@ static bool shouldSwapCmpOperands(SDValue Op0, SDValue Op1,
if (COp1 && COp1->getZExtValue() == 0)
return false;
// Also keep natural memory operands second if the loaded value is
// only used here. Several comparisons have memory forms.
if (isNaturalMemoryOperand(Op1, ICmpType) && Op1.hasOneUse())
return false;
// Look for cases where Cmp0 is a single-use load and Cmp1 isn't.
// In that case we generally prefer the memory to be second.
if ((isNaturalMemoryOperand(Op0, ICmpType) && Op0.hasOneUse()) &&
!(isNaturalMemoryOperand(Op1, ICmpType) && Op1.hasOneUse())) {
if (isNaturalMemoryOperand(Op0, ICmpType) && Op0.hasOneUse()) {
// The only exceptions are when the second operand is a constant and
// we can use things like CHHSI.
if (!COp1)
@@ -1227,6 +1231,19 @@ static bool shouldSwapCmpOperands(SDValue Op0, SDValue Op1,
return false;
return true;
}
// Try to promote the use of CGFR and CLGFR.
unsigned Opcode0 = Op0.getOpcode();
if (ICmpType != SystemZICMP::UnsignedOnly && Opcode0 == ISD::SIGN_EXTEND)
return true;
if (ICmpType != SystemZICMP::SignedOnly && Opcode0 == ISD::ZERO_EXTEND)
return true;
if (ICmpType != SystemZICMP::SignedOnly &&
Opcode0 == ISD::AND &&
Op0.getOperand(1).getOpcode() == ISD::Constant &&
cast<ConstantSDNode>(Op0.getOperand(1))->getZExtValue() == 0xffffffff)
return true;
return false;
}