Add target-specific dag combines for FAND(x,0) and FOR(x,0). This allows
us to compile:
double test(double X) {
return copysign(0.0, X);
}
into:
_test:
andpd LCPI1_0(%rip), %xmm0
ret
instead of:
_test:
pxor %xmm1, %xmm1
andpd LCPI1_0(%rip), %xmm1
movapd %xmm0, %xmm2
andpd LCPI1_1(%rip), %xmm2
movapd %xmm1, %xmm0
orpd %xmm2, %xmm0
ret
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46344 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 9ca99fe..cef8e4b 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -5627,16 +5627,42 @@
return SDOperand();
}
+/// PerformFORCombine - Do target-specific dag combines on X86ISD::FOR nodes.
+static SDOperand PerformFORCombine(SDNode *N, SelectionDAG &DAG) {
+ // FOR(0.0, x) -> x
+ // FOR(x, 0.0) -> x
+ if (ConstantFPSDNode *C = dyn_cast<ConstantFPSDNode>(N->getOperand(0)))
+ if (C->getValueAPF().isPosZero())
+ return N->getOperand(1);
+ if (ConstantFPSDNode *C = dyn_cast<ConstantFPSDNode>(N->getOperand(1)))
+ if (C->getValueAPF().isPosZero())
+ return N->getOperand(0);
+ return SDOperand();
+}
+
+/// PerformFANDCombine - Do target-specific dag combines on X86ISD::FAND nodes.
+static SDOperand PerformFANDCombine(SDNode *N, SelectionDAG &DAG) {
+ // FAND(0.0, x) -> 0.0
+ // FAND(x, 0.0) -> 0.0
+ if (ConstantFPSDNode *C = dyn_cast<ConstantFPSDNode>(N->getOperand(0)))
+ if (C->getValueAPF().isPosZero())
+ return N->getOperand(0);
+ if (ConstantFPSDNode *C = dyn_cast<ConstantFPSDNode>(N->getOperand(1)))
+ if (C->getValueAPF().isPosZero())
+ return N->getOperand(1);
+ return SDOperand();
+}
+
SDOperand X86TargetLowering::PerformDAGCombine(SDNode *N,
DAGCombinerInfo &DCI) const {
SelectionDAG &DAG = DCI.DAG;
switch (N->getOpcode()) {
default: break;
- case ISD::VECTOR_SHUFFLE:
- return PerformShuffleCombine(N, DAG, Subtarget);
- case ISD::SELECT:
- return PerformSELECTCombine(N, DAG, Subtarget);
+ case ISD::VECTOR_SHUFFLE: return PerformShuffleCombine(N, DAG, Subtarget);
+ case ISD::SELECT: return PerformSELECTCombine(N, DAG, Subtarget);
+ case X86ISD::FOR: return PerformFORCombine(N, DAG);
+ case X86ISD::FAND: return PerformFANDCombine(N, DAG);
}
return SDOperand();