[llvm] [DAG] foldABSToABD - support abs(*ext(x) - *ext(y)) -> zext(abd*(x, y)) from different extension source types (PR #71670)
Simon Pilgrim via llvm-commits
llvm-commits at lists.llvm.org
Mon Nov 13 08:56:42 PST 2023
https://github.com/RKSimon updated https://github.com/llvm/llvm-project/pull/71670
>From b9098eac353e62b86a54c45ce4b89f15793bb1a0 Mon Sep 17 00:00:00 2001
From: Simon Pilgrim <llvm-dev at redking.me.uk>
Date: Wed, 8 Nov 2023 12:21:01 +0000
Subject: [PATCH] [DAG] foldABSToABD - support abs(*ext(x) - *ext(y)) ->
zext(abd*(x, y)) from different extension source types
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).
---
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 11 +--
llvm/test/CodeGen/X86/abds.ll | 75 +++++++------------
llvm/test/CodeGen/X86/abdu.ll | 60 +++++++--------
3 files changed, 63 insertions(+), 83 deletions(-)
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index a867d88f76c0cf6..f33110c92355a23 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -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);
}
diff --git a/llvm/test/CodeGen/X86/abds.ll b/llvm/test/CodeGen/X86/abds.ll
index c5be2474c84d405..39ac47e99e6e989 100644
--- a/llvm/test/CodeGen/X86/abds.ll
+++ b/llvm/test/CodeGen/X86/abds.ll
@@ -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
@@ -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
@@ -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
diff --git a/llvm/test/CodeGen/X86/abdu.ll b/llvm/test/CodeGen/X86/abdu.ll
index fe805528c435a52..11719be4ab5cd0c 100644
--- a/llvm/test/CodeGen/X86/abdu.ll
+++ b/llvm/test/CodeGen/X86/abdu.ll
@@ -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
@@ -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
@@ -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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