Summary:
Split off form D46031.
It seems we don't want to transform the pattern if the `xor`'s are actually `not`'s.
In vector case, this breaks `andnpd` / `vandnps` patterns.
That being said, we may want to re-visit this `not` handling, maybe in D46073.
Reviewers: spatel, craig.topper, javed.absar
Reviewed By: spatel
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D46492
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@331595
91177308-0d34-0410-b5e6-
96231b3b80d8
// | D |
// Into:
// (x & m) | (y & ~m)
+// NOTE: we don't unfold the pattern if 'xor' is actually a 'not', because at
+// the very least that breaks andnpd / andnps patterns, and because those
+// patterns are simplified in IR and shouldn't be created in the DAG
SDValue DAGCombiner::unfoldMaskedMerge(SDNode *N) {
assert(N->getOpcode() == ISD::XOR);
+ // Don't touch 'not' (i.e. where y = -1).
+ if (isAllOnesConstantOrAllOnesSplatConstant(N->getOperand(1)))
+ return SDValue();
+
EVT VT = N->getValueType(0);
// FIXME
return false;
SDValue Xor0 = Xor.getOperand(0);
SDValue Xor1 = Xor.getOperand(1);
+ // Don't touch 'not' (i.e. where y = -1).
+ if (isAllOnesConstantOrAllOnesSplatConstant(Xor1))
+ return false;
if (Other == Xor0)
std::swap(Xor0, Xor1);
if (Other != Xor1)
define i32 @in_constant_varx_mone(i32 %x, i32 %y, i32 %mask) {
; CHECK-LABEL: in_constant_varx_mone:
; CHECK: // %bb.0:
-; CHECK-NEXT: and w8, w0, w2
-; CHECK-NEXT: orn w0, w8, w2
+; CHECK-NEXT: bic w8, w2, w0
+; CHECK-NEXT: mvn w0, w8
; CHECK-NEXT: ret
%n0 = xor i32 %x, -1 ; %x
%n1 = and i32 %n0, %mask
define i32 @in_constant_varx_mone_invmask(i32 %x, i32 %y, i32 %mask) {
; CHECK-LABEL: in_constant_varx_mone_invmask:
; CHECK: // %bb.0:
-; CHECK-NEXT: bic w8, w0, w2
-; CHECK-NEXT: orr w0, w8, w2
+; CHECK-NEXT: mvn w8, w0
+; CHECK-NEXT: bic w8, w8, w2
+; CHECK-NEXT: mvn w0, w8
; CHECK-NEXT: ret
%notmask = xor i32 %mask, -1
%n0 = xor i32 %x, -1 ; %x
define i32 @in_constant_mone_vary(i32 %x, i32 %y, i32 %mask) {
; CHECK-LABEL: in_constant_mone_vary:
; CHECK: // %bb.0:
-; CHECK-NEXT: bic w8, w1, w2
-; CHECK-NEXT: orr w0, w2, w8
+; CHECK-NEXT: bic w8, w2, w1
+; CHECK-NEXT: eor w0, w8, w1
; CHECK-NEXT: ret
%n0 = xor i32 -1, %y ; %x
%n1 = and i32 %n0, %mask
define i32 @in_constant_mone_vary_invmask(i32 %x, i32 %y, i32 %mask) {
; CHECK-LABEL: in_constant_mone_vary_invmask:
; CHECK: // %bb.0:
-; CHECK-NEXT: and w8, w1, w2
-; CHECK-NEXT: orn w0, w8, w2
+; CHECK-NEXT: mvn w8, w1
+; CHECK-NEXT: bic w8, w8, w2
+; CHECK-NEXT: eor w0, w8, w1
; CHECK-NEXT: ret
%notmask = xor i32 %mask, -1
%n0 = xor i32 -1, %y ; %x
;
; CHECK-BMI-LABEL: in_constant_varx_mone:
; CHECK-BMI: # %bb.0:
-; CHECK-BMI-NEXT: andl %edx, %edi
-; CHECK-BMI-NEXT: notl %edx
-; CHECK-BMI-NEXT: orl %edi, %edx
-; CHECK-BMI-NEXT: movl %edx, %eax
+; CHECK-BMI-NEXT: andnl %edx, %edi, %eax
+; CHECK-BMI-NEXT: notl %eax
; CHECK-BMI-NEXT: retq
%n0 = xor i32 %x, -1 ; %x
%n1 = and i32 %n0, %mask
;
; CHECK-BMI-LABEL: in_constant_varx_mone_invmask:
; CHECK-BMI: # %bb.0:
-; CHECK-BMI-NEXT: andnl %edi, %edx, %eax
-; CHECK-BMI-NEXT: orl %edx, %eax
+; CHECK-BMI-NEXT: notl %edx
+; CHECK-BMI-NEXT: andnl %edx, %edi, %eax
+; CHECK-BMI-NEXT: notl %eax
; CHECK-BMI-NEXT: retq
%notmask = xor i32 %mask, -1
%n0 = xor i32 %x, -1 ; %x
;
; CHECK-BMI-LABEL: in_constant_mone_vary:
; CHECK-BMI: # %bb.0:
-; CHECK-BMI-NEXT: andnl %esi, %edx, %eax
-; CHECK-BMI-NEXT: orl %edx, %eax
+; CHECK-BMI-NEXT: andnl %edx, %esi, %eax
+; CHECK-BMI-NEXT: xorl %esi, %eax
; CHECK-BMI-NEXT: retq
%n0 = xor i32 -1, %y ; %x
%n1 = and i32 %n0, %mask
;
; CHECK-BMI-LABEL: in_constant_mone_vary_invmask:
; CHECK-BMI: # %bb.0:
-; CHECK-BMI-NEXT: andl %edx, %esi
; CHECK-BMI-NEXT: notl %edx
-; CHECK-BMI-NEXT: orl %esi, %edx
-; CHECK-BMI-NEXT: movl %edx, %eax
+; CHECK-BMI-NEXT: andnl %edx, %esi, %eax
+; CHECK-BMI-NEXT: xorl %esi, %eax
; CHECK-BMI-NEXT: retq
%notmask = xor i32 %mask, -1
%n0 = xor i32 -1, %y ; %x