Skip to content

[SelectionDAG] Propagate poison in getNode with two operands if the input is poison. #135387

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 8 commits into from
Apr 17, 2025
Merged

[SelectionDAG] Propagate poison in getNode with two operands if the input is poison. #135387

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
8 commits
Select commit Hold shift + click to select a range
273f4de
return POISON value in the getNode() in input is poison
diggerlin Apr 11, 2025
bea1bbd
address comment
diggerlin Apr 14, 2025
24661e2
using getPOISON(VT) instead of N2
diggerlin Apr 15, 2025
bd1e9e9
minor change
diggerlin Apr 15, 2025
f0b06ba
address comment
diggerlin Apr 16, 2025
7c196c5
Update llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
diggerlin Apr 16, 2025
a6e0c88
Update llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
diggerlin Apr 16, 2025
24bc9f0
add a nit comment
diggerlin Apr 16, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
19 changes: 14 additions & 5 deletions llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -7573,15 +7573,18 @@ SDValue SelectionDAG::getNode(unsigned Opcode, const SDLoc &DL, EVT VT,
} else {
switch (Opcode) {
case ISD::SUB:
return getUNDEF(VT); // fold op(undef, arg2) -> undef
// fold op(undef, arg2) -> undef, fold op(poison, arg2) ->poison.
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Comment nit.

Suggested change
// fold op(undef, arg2) -> undef, fold op(poison, arg2) ->poison.
// fold op(undef, arg2) -> undef, fold op(poison, arg2) -> poison.

return N1.getOpcode() == ISD::POISON ? getPOISON(VT) : getUNDEF(VT);
case ISD::SIGN_EXTEND_INREG:
case ISD::UDIV:
case ISD::SDIV:
case ISD::UREM:
case ISD::SREM:
case ISD::SSUBSAT:
case ISD::USUBSAT:
return getConstant(0, DL, VT); // fold op(undef, arg2) -> 0
// fold op(undef, arg2) -> 0, fold op(poison, arg2) -> poison.
return N1.getOpcode() == ISD::POISON ? getPOISON(VT)
: getConstant(0, DL, VT);
}
}
}
Expand All @@ -7601,16 +7604,22 @@ SDValue SelectionDAG::getNode(unsigned Opcode, const SDLoc &DL, EVT VT,
case ISD::SDIV:
case ISD::UREM:
case ISD::SREM:
return getUNDEF(VT); // fold op(arg1, undef) -> undef
// fold op(arg1, undef) -> undef, fold op(arg1, poison) -> poison.
return N2.getOpcode() == ISD::POISON ? getPOISON(VT) : getUNDEF(VT);
case ISD::MUL:
case ISD::AND:
case ISD::SSUBSAT:
case ISD::USUBSAT:
return getConstant(0, DL, VT); // fold op(arg1, undef) -> 0
// fold op(arg1, undef) -> 0, fold op(arg1, poison) -> poison.
return N2.getOpcode() == ISD::POISON ? getPOISON(VT)
: getConstant(0, DL, VT);
case ISD::OR:
case ISD::SADDSAT:
case ISD::UADDSAT:
return getAllOnesConstant(DL, VT);
// fold op(arg1, undef) -> an all-ones constant, fold op(arg1, poison) ->
// poison.
return N2.getOpcode() == ISD::POISON ? getPOISON(VT)
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Nit: maybe we can add a similar comment, like the other cases?

: getAllOnesConstant(DL, VT);
}
}

Expand Down
24 changes: 12 additions & 12 deletions llvm/test/CodeGen/X86/half.ll
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1991,8 +1991,8 @@ define void @pr63114() {
; CHECK-LIBCALL-LABEL: pr63114:
; CHECK-LIBCALL: # %bb.0:
; CHECK-LIBCALL-NEXT: movdqu (%rax), %xmm4
; CHECK-LIBCALL-NEXT: pshufhw {{.*#+}} xmm0 = xmm4[0,1,2,3,4,5,7,7]
; CHECK-LIBCALL-NEXT: pshufd {{.*#+}} xmm0 = xmm0[0,2,2,3]
; CHECK-LIBCALL-NEXT: pshuflw {{.*#+}} xmm0 = xmm4[0,1,3,3,4,5,6,7]
; CHECK-LIBCALL-NEXT: pshufd {{.*#+}} xmm0 = xmm0[0,0,2,1]
; CHECK-LIBCALL-NEXT: movdqa {{.*#+}} xmm1 = [65535,65535,65535,0,65535,65535,65535,65535]
; CHECK-LIBCALL-NEXT: pand %xmm1, %xmm0
; CHECK-LIBCALL-NEXT: movq {{.*#+}} xmm2 = [0,0,0,15360,0,0,0,0]
Expand All @@ -2001,8 +2001,8 @@ define void @pr63114() {
; CHECK-LIBCALL-NEXT: pand %xmm3, %xmm0
; CHECK-LIBCALL-NEXT: movdqa {{.*#+}} xmm5 = [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,60]
; CHECK-LIBCALL-NEXT: por %xmm5, %xmm0
; CHECK-LIBCALL-NEXT: pshuflw {{.*#+}} xmm6 = xmm4[0,1,3,3,4,5,6,7]
; CHECK-LIBCALL-NEXT: pshufd {{.*#+}} xmm6 = xmm6[0,0,2,1]
; CHECK-LIBCALL-NEXT: pshufhw {{.*#+}} xmm6 = xmm4[0,1,2,3,4,5,7,7]
; CHECK-LIBCALL-NEXT: pshufd {{.*#+}} xmm6 = xmm6[0,2,2,3]
; CHECK-LIBCALL-NEXT: pand %xmm1, %xmm6
; CHECK-LIBCALL-NEXT: por %xmm2, %xmm6
; CHECK-LIBCALL-NEXT: pand %xmm3, %xmm6
Expand All @@ -2020,8 +2020,8 @@ define void @pr63114() {
; CHECK-LIBCALL-NEXT: por %xmm5, %xmm7
; CHECK-LIBCALL-NEXT: movdqu %xmm7, 0
; CHECK-LIBCALL-NEXT: movdqu %xmm4, 32
; CHECK-LIBCALL-NEXT: movdqu %xmm6, 16
; CHECK-LIBCALL-NEXT: movdqu %xmm0, 48
; CHECK-LIBCALL-NEXT: movdqu %xmm6, 48
; CHECK-LIBCALL-NEXT: movdqu %xmm0, 16
; CHECK-LIBCALL-NEXT: retq
;
; BWON-F16C-LABEL: pr63114:
Expand Down Expand Up @@ -2056,8 +2056,8 @@ define void @pr63114() {
; CHECK-I686-LABEL: pr63114:
; CHECK-I686: # %bb.0:
; CHECK-I686-NEXT: movdqu (%eax), %xmm6
; CHECK-I686-NEXT: pshufhw {{.*#+}} xmm0 = xmm6[0,1,2,3,4,5,7,7]
; CHECK-I686-NEXT: pshufd {{.*#+}} xmm0 = xmm0[0,2,2,3]
; CHECK-I686-NEXT: pshuflw {{.*#+}} xmm0 = xmm6[0,1,3,3,4,5,6,7]
; CHECK-I686-NEXT: pshufd {{.*#+}} xmm0 = xmm0[0,0,2,1]
; CHECK-I686-NEXT: movdqa {{.*#+}} xmm1 = [65535,65535,65535,0,65535,65535,65535,65535]
; CHECK-I686-NEXT: pand %xmm1, %xmm0
; CHECK-I686-NEXT: movq {{.*#+}} xmm2 = [0,0,0,15360,0,0,0,0]
Expand All @@ -2066,8 +2066,8 @@ define void @pr63114() {
; CHECK-I686-NEXT: pand %xmm3, %xmm0
; CHECK-I686-NEXT: movdqa {{.*#+}} xmm4 = [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,60]
; CHECK-I686-NEXT: por %xmm4, %xmm0
; CHECK-I686-NEXT: pshuflw {{.*#+}} xmm5 = xmm6[0,1,3,3,4,5,6,7]
; CHECK-I686-NEXT: pshufd {{.*#+}} xmm5 = xmm5[0,0,2,1]
; CHECK-I686-NEXT: pshufhw {{.*#+}} xmm5 = xmm6[0,1,2,3,4,5,7,7]
; CHECK-I686-NEXT: pshufd {{.*#+}} xmm5 = xmm5[0,2,2,3]
; CHECK-I686-NEXT: pand %xmm1, %xmm5
; CHECK-I686-NEXT: por %xmm2, %xmm5
; CHECK-I686-NEXT: pand %xmm3, %xmm5
Expand All @@ -2085,8 +2085,8 @@ define void @pr63114() {
; CHECK-I686-NEXT: por %xmm4, %xmm7
; CHECK-I686-NEXT: movdqu %xmm7, 0
; CHECK-I686-NEXT: movdqu %xmm6, 32
; CHECK-I686-NEXT: movdqu %xmm5, 16
; CHECK-I686-NEXT: movdqu %xmm0, 48
; CHECK-I686-NEXT: movdqu %xmm5, 48
; CHECK-I686-NEXT: movdqu %xmm0, 16
; CHECK-I686-NEXT: retl
%1 = load <24 x half>, ptr poison, align 2
%2 = shufflevector <24 x half> %1, <24 x half> poison, <8 x i32> <i32 2, i32 5, i32 8, i32 11, i32 14, i32 17, i32 20, i32 23>
Expand Down
20 changes: 0 additions & 20 deletions llvm/test/CodeGen/X86/poison-ops.ll
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -68,7 +68,6 @@ define <4 x i32> @sub_poison_lhs_vec(<4 x i32> %x) {
define i32 @mul_poison_rhs(i32 %x) {
; CHECK-LABEL: mul_poison_rhs:
; CHECK: # %bb.0:
; CHECK-NEXT: xorl %eax, %eax
; CHECK-NEXT: retq
%r = mul i32 %x, poison
ret i32 %r
Expand All @@ -77,7 +76,6 @@ define i32 @mul_poison_rhs(i32 %x) {
define <4 x i32> @mul_poison_rhs_vec(<4 x i32> %x) {
; CHECK-LABEL: mul_poison_rhs_vec:
; CHECK: # %bb.0:
; CHECK-NEXT: xorps %xmm0, %xmm0
; CHECK-NEXT: retq
%r = mul <4 x i32> %x, poison
ret <4 x i32> %r
Expand All @@ -86,7 +84,6 @@ define <4 x i32> @mul_poison_rhs_vec(<4 x i32> %x) {
define i32 @mul_poison_lhs(i32 %x) {
; CHECK-LABEL: mul_poison_lhs:
; CHECK: # %bb.0:
; CHECK-NEXT: xorl %eax, %eax
; CHECK-NEXT: retq
%r = mul i32 poison, %x
ret i32 %r
Expand All @@ -95,7 +92,6 @@ define i32 @mul_poison_lhs(i32 %x) {
define <4 x i32> @mul_poison_lhs_vec(<4 x i32> %x) {
; CHECK-LABEL: mul_poison_lhs_vec:
; CHECK: # %bb.0:
; CHECK-NEXT: xorps %xmm0, %xmm0
; CHECK-NEXT: retq
%r = mul <4 x i32> poison, %x
ret <4 x i32> %r
Expand All @@ -120,7 +116,6 @@ define <4 x i32> @sdiv_poison_rhs_vec(<4 x i32> %x) {
define i32 @sdiv_poison_lhs(i32 %x) {
; CHECK-LABEL: sdiv_poison_lhs:
; CHECK: # %bb.0:
; CHECK-NEXT: xorl %eax, %eax
; CHECK-NEXT: retq
%r = sdiv i32 poison, %x
ret i32 %r
Expand All @@ -129,7 +124,6 @@ define i32 @sdiv_poison_lhs(i32 %x) {
define <4 x i32> @sdiv_poison_lhs_vec(<4 x i32> %x) {
; CHECK-LABEL: sdiv_poison_lhs_vec:
; CHECK: # %bb.0:
; CHECK-NEXT: xorps %xmm0, %xmm0
; CHECK-NEXT: retq
%r = sdiv <4 x i32> poison, %x
ret <4 x i32> %r
Expand All @@ -154,7 +148,6 @@ define <4 x i32> @udiv_poison_rhs_vec(<4 x i32> %x) {
define i32 @udiv_poison_lhs(i32 %x) {
; CHECK-LABEL: udiv_poison_lhs:
; CHECK: # %bb.0:
; CHECK-NEXT: xorl %eax, %eax
; CHECK-NEXT: retq
%r = udiv i32 poison, %x
ret i32 %r
Expand All @@ -163,7 +156,6 @@ define i32 @udiv_poison_lhs(i32 %x) {
define <4 x i32> @udiv_poison_lhs_vec(<4 x i32> %x) {
; CHECK-LABEL: udiv_poison_lhs_vec:
; CHECK: # %bb.0:
; CHECK-NEXT: xorps %xmm0, %xmm0
; CHECK-NEXT: retq
%r = udiv <4 x i32> poison, %x
ret <4 x i32> %r
Expand All @@ -188,7 +180,6 @@ define <4 x i32> @srem_poison_rhs_vec(<4 x i32> %x) {
define i32 @srem_poison_lhs(i32 %x) {
; CHECK-LABEL: srem_poison_lhs:
; CHECK: # %bb.0:
; CHECK-NEXT: xorl %eax, %eax
; CHECK-NEXT: retq
%r = srem i32 poison, %x
ret i32 %r
Expand All @@ -197,7 +188,6 @@ define i32 @srem_poison_lhs(i32 %x) {
define <4 x i32> @srem_poison_lhs_vec(<4 x i32> %x) {
; CHECK-LABEL: srem_poison_lhs_vec:
; CHECK: # %bb.0:
; CHECK-NEXT: xorps %xmm0, %xmm0
; CHECK-NEXT: retq
%r = srem <4 x i32> poison, %x
ret <4 x i32> %r
Expand All @@ -222,7 +212,6 @@ define <4 x i32> @urem_poison_rhs_vec(<4 x i32> %x) {
define i32 @urem_poison_lhs(i32 %x) {
; CHECK-LABEL: urem_poison_lhs:
; CHECK: # %bb.0:
; CHECK-NEXT: xorl %eax, %eax
; CHECK-NEXT: retq
%r = urem i32 poison, %x
ret i32 %r
Expand All @@ -231,7 +220,6 @@ define i32 @urem_poison_lhs(i32 %x) {
define <4 x i32> @urem_poison_lhs_vec(<4 x i32> %x) {
; CHECK-LABEL: urem_poison_lhs_vec:
; CHECK: # %bb.0:
; CHECK-NEXT: xorps %xmm0, %xmm0
; CHECK-NEXT: retq
%r = urem <4 x i32> poison, %x
ret <4 x i32> %r
Expand Down Expand Up @@ -342,7 +330,6 @@ define <4 x i32> @shl_poison_lhs_vec(<4 x i32> %x) {
define i32 @and_poison_rhs(i32 %x) {
; CHECK-LABEL: and_poison_rhs:
; CHECK: # %bb.0:
; CHECK-NEXT: xorl %eax, %eax
; CHECK-NEXT: retq
%r = and i32 %x, poison
ret i32 %r
Expand All @@ -351,7 +338,6 @@ define i32 @and_poison_rhs(i32 %x) {
define <4 x i32> @and_poison_rhs_vec(<4 x i32> %x) {
; CHECK-LABEL: and_poison_rhs_vec:
; CHECK: # %bb.0:
; CHECK-NEXT: xorps %xmm0, %xmm0
; CHECK-NEXT: retq
%r = and <4 x i32> %x, poison
ret <4 x i32> %r
Expand All @@ -360,7 +346,6 @@ define <4 x i32> @and_poison_rhs_vec(<4 x i32> %x) {
define i32 @and_poison_lhs(i32 %x) {
; CHECK-LABEL: and_poison_lhs:
; CHECK: # %bb.0:
; CHECK-NEXT: xorl %eax, %eax
; CHECK-NEXT: retq
%r = and i32 poison, %x
ret i32 %r
Expand All @@ -369,7 +354,6 @@ define i32 @and_poison_lhs(i32 %x) {
define <4 x i32> @and_poison_lhs_vec(<4 x i32> %x) {
; CHECK-LABEL: and_poison_lhs_vec:
; CHECK: # %bb.0:
; CHECK-NEXT: xorps %xmm0, %xmm0
; CHECK-NEXT: retq
%r = and <4 x i32> poison, %x
ret <4 x i32> %r
Expand All @@ -378,7 +362,6 @@ define <4 x i32> @and_poison_lhs_vec(<4 x i32> %x) {
define i32 @or_poison_rhs(i32 %x) {
; CHECK-LABEL: or_poison_rhs:
; CHECK: # %bb.0:
; CHECK-NEXT: movl $-1, %eax
; CHECK-NEXT: retq
%r = or i32 %x, poison
ret i32 %r
Expand All @@ -387,7 +370,6 @@ define i32 @or_poison_rhs(i32 %x) {
define <4 x i32> @or_poison_rhs_vec(<4 x i32> %x) {
; CHECK-LABEL: or_poison_rhs_vec:
; CHECK: # %bb.0:
; CHECK-NEXT: pcmpeqd %xmm0, %xmm0
; CHECK-NEXT: retq
%r = or <4 x i32> %x, poison
ret <4 x i32> %r
Expand All @@ -396,7 +378,6 @@ define <4 x i32> @or_poison_rhs_vec(<4 x i32> %x) {
define i32 @or_poison_lhs(i32 %x) {
; CHECK-LABEL: or_poison_lhs:
; CHECK: # %bb.0:
; CHECK-NEXT: movl $-1, %eax
; CHECK-NEXT: retq
%r = or i32 poison, %x
ret i32 %r
Expand All @@ -405,7 +386,6 @@ define i32 @or_poison_lhs(i32 %x) {
define <4 x i32> @or_poison_lhs_vec(<4 x i32> %x) {
; CHECK-LABEL: or_poison_lhs_vec:
; CHECK: # %bb.0:
; CHECK-NEXT: pcmpeqd %xmm0, %xmm0
; CHECK-NEXT: retq
%r = or <4 x i32> poison, %x
ret <4 x i32> %r
Expand Down
7 changes: 3 additions & 4 deletions llvm/test/CodeGen/X86/pr119158.ll
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -5,10 +5,9 @@ define dso_local void @foo() #1 {
; CHECK-LABEL: foo:
; CHECK: # %bb.0: # %newFuncRoot
; CHECK-NEXT: vpmovzxbd {{.*#+}} ymm0 = mem[0],zero,zero,zero,mem[1],zero,zero,zero,mem[2],zero,zero,zero,mem[3],zero,zero,zero,mem[4],zero,zero,zero,mem[5],zero,zero,zero,mem[6],zero,zero,zero,mem[7],zero,zero,zero
; CHECK-NEXT: vpbroadcastd {{.*#+}} ymm1 = [18,0,18,0,18,0,18,0,18,0,18,0,18,0,18,0]
; CHECK-NEXT: vpmaddwd %ymm1, %ymm0, %ymm0
; CHECK-NEXT: vpaddd {{\.?LCPI[0-9]+_[0-9]+}}(%rip){1to8}, %ymm0, %ymm0
; CHECK-NEXT: vpsrld $7, %ymm0, %ymm0
; CHECK-NEXT: vpbroadcastd {{.*#+}} ymm1 = [64,64,64,64,64,64,64,64]
; CHECK-NEXT: vpdpwssd {{\.?LCPI[0-9]+_[0-9]+}}(%rip){1to8}, %ymm0, %ymm1
; CHECK-NEXT: vpsrld $7, %ymm1, %ymm0
; CHECK-NEXT: vpackusdw %ymm0, %ymm0, %ymm0
; CHECK-NEXT: vpermq {{.*#+}} ymm0 = ymm0[0,2,1,3]
; CHECK-NEXT: vmovdqu %ymm0, (%rax)
Expand Down
Loading