Fix the bfi handling for or (and a mask) (and b mask). We need the two
masks to match inversely for the code as is to work. For the example given
we actually want:
bfi r0, r2, #1, #1
not #0, however, given the way the pattern is written it's not possible
at the moment.
Fixes rdar://9177502
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128320 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMISelLowering.cpp b/lib/Target/ARM/ARMISelLowering.cpp
index 891ea62..623393d 100644
--- a/lib/Target/ARM/ARMISelLowering.cpp
+++ b/lib/Target/ARM/ARMISelLowering.cpp
@@ -5168,6 +5168,7 @@
static SDValue PerformANDCombine(SDNode *N,
TargetLowering::DAGCombinerInfo &DCI) {
+
// Attempt to use immediate-form VBIC
BuildVectorSDNode *BVN = dyn_cast<BuildVectorSDNode>(N->getOperand(1));
DebugLoc dl = N->getDebugLoc();
@@ -5241,9 +5242,9 @@
//
// 2) or (and A, mask), (and B, mask2) => ARMbfi A, (lsr B, amt), mask
// 2a) iff isBitFieldInvertedMask(mask) && isBitFieldInvertedMask(~mask2)
- // && CountPopulation_32(mask) == CountPopulation_32(~mask2)
+ // && mask == ~mask2
// 2b) iff isBitFieldInvertedMask(~mask) && isBitFieldInvertedMask(mask2)
- // && CountPopulation_32(mask) == CountPopulation_32(~mask2)
+ // && ~mask == mask2
// (i.e., copy a bitfield value into another bitfield of the same width)
if (N0.getOpcode() != ISD::AND)
return SDValue();
@@ -5289,26 +5290,26 @@
return SDValue();
unsigned Mask2 = N11C->getZExtValue();
+ // Mask and ~Mask2 (or reverse) must be equivalent for the BFI pattern
+ // as is to match.
if (ARM::isBitFieldInvertedMask(Mask) &&
- ARM::isBitFieldInvertedMask(~Mask2) &&
- (CountPopulation_32(Mask) == CountPopulation_32(~Mask2))) {
+ (Mask == ~Mask2)) {
// The pack halfword instruction works better for masks that fit it,
// so use that when it's available.
if (Subtarget->hasT2ExtractPack() &&
(Mask == 0xffff || Mask == 0xffff0000))
return SDValue();
// 2a
- unsigned lsb = CountTrailingZeros_32(Mask2);
+ unsigned amt = CountTrailingZeros_32(Mask2);
Res = DAG.getNode(ISD::SRL, DL, VT, N1.getOperand(0),
- DAG.getConstant(lsb, MVT::i32));
+ DAG.getConstant(amt, MVT::i32));
Res = DAG.getNode(ARMISD::BFI, DL, VT, N00, Res,
DAG.getConstant(Mask, MVT::i32));
// Do not add new nodes to DAG combiner worklist.
DCI.CombineTo(N, Res, false);
return SDValue();
} else if (ARM::isBitFieldInvertedMask(~Mask) &&
- ARM::isBitFieldInvertedMask(Mask2) &&
- (CountPopulation_32(~Mask) == CountPopulation_32(Mask2))) {
+ (~Mask == Mask2)) {
// The pack halfword instruction works better for masks that fit it,
// so use that when it's available.
if (Subtarget->hasT2ExtractPack() &&
@@ -5319,7 +5320,7 @@
Res = DAG.getNode(ISD::SRL, DL, VT, N00,
DAG.getConstant(lsb, MVT::i32));
Res = DAG.getNode(ARMISD::BFI, DL, VT, N1.getOperand(0), Res,
- DAG.getConstant(Mask2, MVT::i32));
+ DAG.getConstant(Mask2, MVT::i32));
// Do not add new nodes to DAG combiner worklist.
DCI.CombineTo(N, Res, false);
return SDValue();