Inform the dag combiner that the predicate compares only return a low bit.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@27359 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/PowerPC/PPCISelLowering.cpp b/lib/Target/PowerPC/PPCISelLowering.cpp
index 03e63a2..06096a7 100644
--- a/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -760,7 +760,7 @@
return DAG.getNode(PPCISD::VPERM, V1.getValueType(), V1, V2, VPermMask);
}
case ISD::INTRINSIC_WO_CHAIN: {
- unsigned IntNo=cast<ConstantSDNode>(Op.getOperand(0))->getValue();
+ unsigned IntNo = cast<ConstantSDNode>(Op.getOperand(0))->getValue();
// If this is a lowered altivec predicate compare, CompareOpc is set to the
// opcode number of the comparison.
@@ -1409,6 +1409,39 @@
return SDOperand();
}
+void PPCTargetLowering::computeMaskedBitsForTargetNode(const SDOperand Op,
+ uint64_t Mask,
+ uint64_t &KnownZero,
+ uint64_t &KnownOne,
+ unsigned Depth) const {
+ KnownZero = 0;
+ KnownOne = 0;
+ switch (Op.getOpcode()) {
+ default: break;
+ case ISD::INTRINSIC_WO_CHAIN: {
+ switch (cast<ConstantSDNode>(Op.getOperand(0))->getValue()) {
+ default: break;
+ case Intrinsic::ppc_altivec_vcmpbfp_p:
+ case Intrinsic::ppc_altivec_vcmpeqfp_p:
+ case Intrinsic::ppc_altivec_vcmpequb_p:
+ case Intrinsic::ppc_altivec_vcmpequh_p:
+ case Intrinsic::ppc_altivec_vcmpequw_p:
+ case Intrinsic::ppc_altivec_vcmpgefp_p:
+ case Intrinsic::ppc_altivec_vcmpgtfp_p:
+ case Intrinsic::ppc_altivec_vcmpgtsb_p:
+ case Intrinsic::ppc_altivec_vcmpgtsh_p:
+ case Intrinsic::ppc_altivec_vcmpgtsw_p:
+ case Intrinsic::ppc_altivec_vcmpgtub_p:
+ case Intrinsic::ppc_altivec_vcmpgtuh_p:
+ case Intrinsic::ppc_altivec_vcmpgtuw_p:
+ KnownZero = ~1U; // All bits but the low one are known to be zero.
+ break;
+ }
+ }
+ }
+}
+
+
/// getConstraintType - Given a constraint letter, return the type of
/// constraint it is for this target.
PPCTargetLowering::ConstraintType
diff --git a/lib/Target/PowerPC/PPCISelLowering.h b/lib/Target/PowerPC/PPCISelLowering.h
index bc865c6..2fe79ec 100644
--- a/lib/Target/PowerPC/PPCISelLowering.h
+++ b/lib/Target/PowerPC/PPCISelLowering.h
@@ -133,6 +133,11 @@
virtual SDOperand PerformDAGCombine(SDNode *N, DAGCombinerInfo &DCI) const;
+ virtual void computeMaskedBitsForTargetNode(const SDOperand Op,
+ uint64_t Mask,
+ uint64_t &KnownZero,
+ uint64_t &KnownOne,
+ unsigned Depth = 0) const;
/// LowerArguments - This hook must be implemented to indicate how we should
/// lower the arguments for the specified function, into the specified DAG.
virtual std::vector<SDOperand>