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[DAG] foldABSToABD - support abs(*ext(x) - *ext(y)) -> zext(abd*(x, y…
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…)) from different extension source types (#71670)

We currently limit the fold to cases where we're extending from the same source type, but we can safely perform this using the wider of mismatching source types (we're really just interested in having extension bits on both sources), ensuring we don't create additional extensions/truncations.
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@RKSimon
RKSimon committed Nov 14, 2023
1 parent 783ac3b commit 074e4ae
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Showing 4 changed files with 65 additions and 93 deletions.
11 changes: 6 additions & 5 deletions llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -10923,11 +10923,12 @@ SDValue DAGCombiner::foldABSToABD(SDNode *N) {

// fold abs(sext(x) - sext(y)) -> zext(abds(x, y))
// fold abs(zext(x) - zext(y)) -> zext(abdu(x, y))
// NOTE: Extensions must be equivalent.
if (VT1 == VT2 && hasOperation(ABDOpcode, VT1)) {
Op0 = Op0.getOperand(0);
Op1 = Op1.getOperand(0);
SDValue ABD = DAG.getNode(ABDOpcode, DL, VT1, Op0, Op1);
EVT MaxVT = VT1.bitsGT(VT2) ? VT1 : VT2;
if ((VT1 == MaxVT || Op0->hasOneUse()) &&
(VT2 == MaxVT || Op1->hasOneUse()) && hasOperation(ABDOpcode, MaxVT)) {
SDValue ABD = DAG.getNode(ABDOpcode, DL, MaxVT,
DAG.getNode(ISD::TRUNCATE, DL, MaxVT, Op0),
DAG.getNode(ISD::TRUNCATE, DL, MaxVT, Op1));
ABD = DAG.getNode(ISD::ZERO_EXTEND, DL, VT, ABD);
return DAG.getZExtOrTrunc(ABD, DL, SrcVT);
}
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12 changes: 2 additions & 10 deletions llvm/test/CodeGen/AArch64/sve-abd.ll
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Original file line number Diff line number Diff line change
Expand Up @@ -248,17 +248,9 @@ define <vscale x 2 x i64> @uabd_d_promoted_ops(<vscale x 2 x i32> %a, <vscale x
define <vscale x 4 x i32> @uabd_non_matching_extension(<vscale x 4 x i32> %a, <vscale x 4 x i8> %b) #0 {
; CHECK-LABEL: uabd_non_matching_extension:
; CHECK: // %bb.0:
; CHECK-NEXT: ptrue p0.s
; CHECK-NEXT: and z1.s, z1.s, #0xff
; CHECK-NEXT: uunpkhi z2.d, z0.s
; CHECK-NEXT: uunpklo z0.d, z0.s
; CHECK-NEXT: ptrue p0.d
; CHECK-NEXT: uunpkhi z3.d, z1.s
; CHECK-NEXT: uunpklo z1.d, z1.s
; CHECK-NEXT: sub z0.d, z0.d, z1.d
; CHECK-NEXT: sub z1.d, z2.d, z3.d
; CHECK-NEXT: abs z1.d, p0/m, z1.d
; CHECK-NEXT: abs z0.d, p0/m, z0.d
; CHECK-NEXT: uzp1 z0.s, z0.s, z1.s
; CHECK-NEXT: uabd z0.s, p0/m, z0.s, z1.s
; CHECK-NEXT: ret
%a.zext = zext <vscale x 4 x i32> %a to <vscale x 4 x i64>
%b.zext = zext <vscale x 4 x i8> %b to <vscale x 4 x i64>
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75 changes: 29 additions & 46 deletions llvm/test/CodeGen/X86/abds.ll
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Original file line number Diff line number Diff line change
Expand Up @@ -50,16 +50,13 @@ define i8 @abd_ext_i8_i16(i8 %a, i16 %b) nounwind {
;
; X64-LABEL: abd_ext_i8_i16:
; X64: # %bb.0:
; X64-NEXT: # kill: def $esi killed $esi def $rsi
; X64-NEXT: # kill: def $edi killed $edi def $rdi
; X64-NEXT: movsbq %dil, %rax
; X64-NEXT: movswq %si, %rcx
; X64-NEXT: movq %rax, %rdx
; X64-NEXT: subq %rcx, %rdx
; X64-NEXT: negq %rdx
; X64-NEXT: subq %rcx, %rax
; X64-NEXT: cmovleq %rdx, %rax
; X64-NEXT: # kill: def $al killed $al killed $rax
; X64-NEXT: movswl %si, %eax
; X64-NEXT: movsbl %dil, %ecx
; X64-NEXT: subl %eax, %ecx
; X64-NEXT: movl %ecx, %eax
; X64-NEXT: negl %eax
; X64-NEXT: cmovsl %ecx, %eax
; X64-NEXT: # kill: def $al killed $al killed $eax
; X64-NEXT: retq
%aext = sext i8 %a to i64
%bext = sext i16 %b to i64
Expand Down Expand Up @@ -132,32 +129,25 @@ define i16 @abd_ext_i16(i16 %a, i16 %b) nounwind {
define i16 @abd_ext_i16_i32(i16 %a, i32 %b) nounwind {
; X86-LABEL: abd_ext_i16_i32:
; X86: # %bb.0:
; X86-NEXT: pushl %esi
; X86-NEXT: movl {{[0-9]+}}(%esp), %ecx
; X86-NEXT: movl %ecx, %edx
; X86-NEXT: sarl $31, %edx
; X86-NEXT: movswl {{[0-9]+}}(%esp), %eax
; X86-NEXT: movl %eax, %esi
; X86-NEXT: sarl $31, %esi
; X86-NEXT: movl %eax, %edx
; X86-NEXT: subl %ecx, %edx
; X86-NEXT: negl %edx
; X86-NEXT: subl %ecx, %eax
; X86-NEXT: sbbl %edx, %esi
; X86-NEXT: sarl $31, %esi
; X86-NEXT: xorl %esi, %eax
; X86-NEXT: subl %esi, %eax
; X86-NEXT: cmovlel %edx, %eax
; X86-NEXT: # kill: def $ax killed $ax killed $eax
; X86-NEXT: popl %esi
; X86-NEXT: retl
;
; X64-LABEL: abd_ext_i16_i32:
; X64: # %bb.0:
; X64-NEXT: # kill: def $edi killed $edi def $rdi
; X64-NEXT: movswq %di, %rax
; X64-NEXT: movslq %esi, %rcx
; X64-NEXT: movq %rax, %rdx
; X64-NEXT: subq %rcx, %rdx
; X64-NEXT: negq %rdx
; X64-NEXT: subq %rcx, %rax
; X64-NEXT: cmovleq %rdx, %rax
; X64-NEXT: movslq %esi, %rax
; X64-NEXT: movswl %di, %ecx
; X64-NEXT: movslq %ecx, %rcx
; X64-NEXT: subq %rax, %rcx
; X64-NEXT: movq %rcx, %rax
; X64-NEXT: negq %rax
; X64-NEXT: cmovsq %rcx, %rax
; X64-NEXT: # kill: def $ax killed $ax killed $rax
; X64-NEXT: retq
%aext = sext i16 %a to i64
Expand Down Expand Up @@ -231,31 +221,24 @@ define i32 @abd_ext_i32(i32 %a, i32 %b) nounwind {
define i32 @abd_ext_i32_i16(i32 %a, i16 %b) nounwind {
; X86-LABEL: abd_ext_i32_i16:
; X86: # %bb.0:
; X86-NEXT: pushl %esi
; X86-NEXT: movswl {{[0-9]+}}(%esp), %ecx
; X86-NEXT: movl %ecx, %edx
; X86-NEXT: sarl $31, %edx
; X86-NEXT: movl {{[0-9]+}}(%esp), %eax
; X86-NEXT: movl %eax, %esi
; X86-NEXT: sarl $31, %esi
; X86-NEXT: movl %eax, %edx
; X86-NEXT: subl %ecx, %edx
; X86-NEXT: negl %edx
; X86-NEXT: subl %ecx, %eax
; X86-NEXT: sbbl %edx, %esi
; X86-NEXT: sarl $31, %esi
; X86-NEXT: xorl %esi, %eax
; X86-NEXT: subl %esi, %eax
; X86-NEXT: popl %esi
; X86-NEXT: cmovlel %edx, %eax
; X86-NEXT: retl
;
; X64-LABEL: abd_ext_i32_i16:
; X64: # %bb.0:
; X64-NEXT: # kill: def $esi killed $esi def $rsi
; X64-NEXT: movslq %edi, %rax
; X64-NEXT: movswq %si, %rcx
; X64-NEXT: movq %rax, %rdx
; X64-NEXT: subq %rcx, %rdx
; X64-NEXT: negq %rdx
; X64-NEXT: subq %rcx, %rax
; X64-NEXT: cmovleq %rdx, %rax
; X64-NEXT: movslq %edi, %rcx
; X64-NEXT: movswl %si, %eax
; X64-NEXT: cltq
; X64-NEXT: subq %rax, %rcx
; X64-NEXT: movq %rcx, %rax
; X64-NEXT: negq %rax
; X64-NEXT: cmovsq %rcx, %rax
; X64-NEXT: # kill: def $eax killed $eax killed $rax
; X64-NEXT: retq
%aext = sext i32 %a to i64
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60 changes: 28 additions & 32 deletions llvm/test/CodeGen/X86/abdu.ll
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Original file line number Diff line number Diff line change
Expand Up @@ -50,14 +50,13 @@ define i8 @abd_ext_i8_i16(i8 %a, i16 %b) nounwind {
;
; X64-LABEL: abd_ext_i8_i16:
; X64: # %bb.0:
; X64-NEXT: movzbl %dil, %eax
; X64-NEXT: movzwl %si, %ecx
; X64-NEXT: movq %rax, %rdx
; X64-NEXT: subq %rcx, %rdx
; X64-NEXT: negq %rdx
; X64-NEXT: subq %rcx, %rax
; X64-NEXT: cmovbeq %rdx, %rax
; X64-NEXT: # kill: def $al killed $al killed $rax
; X64-NEXT: movzwl %si, %eax
; X64-NEXT: movzbl %dil, %ecx
; X64-NEXT: subl %eax, %ecx
; X64-NEXT: movl %ecx, %eax
; X64-NEXT: negl %eax
; X64-NEXT: cmovsl %ecx, %eax
; X64-NEXT: # kill: def $al killed $al killed $eax
; X64-NEXT: retq
%aext = zext i8 %a to i64
%bext = zext i16 %b to i64
Expand Down Expand Up @@ -130,25 +129,24 @@ define i16 @abd_ext_i16(i16 %a, i16 %b) nounwind {
define i16 @abd_ext_i16_i32(i16 %a, i32 %b) nounwind {
; X86-LABEL: abd_ext_i16_i32:
; X86: # %bb.0:
; X86-NEXT: movl {{[0-9]+}}(%esp), %ecx
; X86-NEXT: movzwl {{[0-9]+}}(%esp), %eax
; X86-NEXT: xorl %ecx, %ecx
; X86-NEXT: subl {{[0-9]+}}(%esp), %eax
; X86-NEXT: sbbl %ecx, %ecx
; X86-NEXT: sarl $31, %ecx
; X86-NEXT: xorl %ecx, %eax
; X86-NEXT: movl %eax, %edx
; X86-NEXT: subl %ecx, %edx
; X86-NEXT: negl %edx
; X86-NEXT: subl %ecx, %eax
; X86-NEXT: cmovbel %edx, %eax
; X86-NEXT: # kill: def $ax killed $ax killed $eax
; X86-NEXT: retl
;
; X64-LABEL: abd_ext_i16_i32:
; X64: # %bb.0:
; X64-NEXT: movzwl %di, %eax
; X64-NEXT: movl %esi, %ecx
; X64-NEXT: movq %rax, %rdx
; X64-NEXT: subq %rcx, %rdx
; X64-NEXT: negq %rdx
; X64-NEXT: subq %rcx, %rax
; X64-NEXT: cmovbeq %rdx, %rax
; X64-NEXT: movl %esi, %eax
; X64-NEXT: movzwl %di, %ecx
; X64-NEXT: subq %rax, %rcx
; X64-NEXT: movq %rcx, %rax
; X64-NEXT: negq %rax
; X64-NEXT: cmovsq %rcx, %rax
; X64-NEXT: # kill: def $ax killed $ax killed $rax
; X64-NEXT: retq
%aext = zext i16 %a to i64
Expand Down Expand Up @@ -224,23 +222,21 @@ define i32 @abd_ext_i32_i16(i32 %a, i16 %b) nounwind {
; X86: # %bb.0:
; X86-NEXT: movzwl {{[0-9]+}}(%esp), %ecx
; X86-NEXT: movl {{[0-9]+}}(%esp), %eax
; X86-NEXT: xorl %edx, %edx
; X86-NEXT: movl %eax, %edx
; X86-NEXT: subl %ecx, %edx
; X86-NEXT: negl %edx
; X86-NEXT: subl %ecx, %eax
; X86-NEXT: sbbl %edx, %edx
; X86-NEXT: sarl $31, %edx
; X86-NEXT: xorl %edx, %eax
; X86-NEXT: subl %edx, %eax
; X86-NEXT: cmovbel %edx, %eax
; X86-NEXT: retl
;
; X64-LABEL: abd_ext_i32_i16:
; X64: # %bb.0:
; X64-NEXT: movl %edi, %eax
; X64-NEXT: movzwl %si, %ecx
; X64-NEXT: movq %rax, %rdx
; X64-NEXT: subq %rcx, %rdx
; X64-NEXT: negq %rdx
; X64-NEXT: subq %rcx, %rax
; X64-NEXT: cmovbeq %rdx, %rax
; X64-NEXT: movl %edi, %ecx
; X64-NEXT: movzwl %si, %eax
; X64-NEXT: subq %rax, %rcx
; X64-NEXT: movq %rcx, %rax
; X64-NEXT: negq %rax
; X64-NEXT: cmovsq %rcx, %rax
; X64-NEXT: # kill: def $eax killed $eax killed $rax
; X64-NEXT: retq
%aext = zext i32 %a to i64
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