[llvm] [X86] narrowBitOpRMW - add tests showing failure to fold to BTC/BTR/BTS RMW patterns (PR #165758)
Simon Pilgrim via llvm-commits
llvm-commits at lists.llvm.org
Thu Oct 30 12:41:26 PDT 2025
https://github.com/RKSimon updated https://github.com/llvm/llvm-project/pull/165758
>From aff15447e49578aba87e6078b84db8f651db6aa3 Mon Sep 17 00:00:00 2001
From: Simon Pilgrim <llvm-dev at redking.me.uk>
Date: Thu, 30 Oct 2025 18:06:21 +0000
Subject: [PATCH] [X86] narrowBitOpRMW - add tests showing failure to fold to
BTC/BTR patterns
Failure to fold if the store's chain doesn't directly touch the RMW load source (we should be using reachesChainWithoutSideEffects to avoid this).
Failure to fold if the stored value has additional uses (we could update other uses of the whole stored value to reload after the new narrow store)
---
llvm/test/CodeGen/X86/bittest-big-integer.ll | 288 +++++++++++++++++++
1 file changed, 288 insertions(+)
diff --git a/llvm/test/CodeGen/X86/bittest-big-integer.ll b/llvm/test/CodeGen/X86/bittest-big-integer.ll
index cc3dcf32ac0eb..06e7d4773c58d 100644
--- a/llvm/test/CodeGen/X86/bittest-big-integer.ll
+++ b/llvm/test/CodeGen/X86/bittest-big-integer.ll
@@ -1676,3 +1676,291 @@ define i1 @test_ne_i4096(ptr %word, i32 %position) nounwind {
%cmp = icmp ne i4096 %test, 0
ret i1 %cmp
}
+
+; Special Cases
+
+; Multiple uses of the stored value
+define i1 @complement_cmpz_i128(ptr %word, i32 %position) nounwind {
+; X86-LABEL: complement_cmpz_i128:
+; X86: # %bb.0:
+; X86-NEXT: pushl %ebp
+; X86-NEXT: movl %esp, %ebp
+; X86-NEXT: pushl %ebx
+; X86-NEXT: pushl %edi
+; X86-NEXT: pushl %esi
+; X86-NEXT: andl $-16, %esp
+; X86-NEXT: subl $64, %esp
+; X86-NEXT: movzbl 12(%ebp), %ecx
+; X86-NEXT: movl $0, {{[0-9]+}}(%esp)
+; X86-NEXT: movl $0, {{[0-9]+}}(%esp)
+; X86-NEXT: movl $0, {{[0-9]+}}(%esp)
+; X86-NEXT: movl $1, {{[0-9]+}}(%esp)
+; X86-NEXT: movl $0, {{[0-9]+}}(%esp)
+; X86-NEXT: movl $0, {{[0-9]+}}(%esp)
+; X86-NEXT: movl $0, {{[0-9]+}}(%esp)
+; X86-NEXT: movl $0, {{[0-9]+}}(%esp)
+; X86-NEXT: movl %ecx, %eax
+; X86-NEXT: shrb $3, %al
+; X86-NEXT: andb $12, %al
+; X86-NEXT: negb %al
+; X86-NEXT: movsbl %al, %esi
+; X86-NEXT: movl 36(%esp,%esi), %eax
+; X86-NEXT: movl 40(%esp,%esi), %edi
+; X86-NEXT: movl %edi, %edx
+; X86-NEXT: shldl %cl, %eax, %edx
+; X86-NEXT: movl 32(%esp,%esi), %ebx
+; X86-NEXT: movl %ebx, {{[-0-9]+}}(%e{{[sb]}}p) # 4-byte Spill
+; X86-NEXT: movl 44(%esp,%esi), %esi
+; X86-NEXT: shldl %cl, %edi, %esi
+; X86-NEXT: movl %ebx, %edi
+; X86-NEXT: shll %cl, %edi
+; X86-NEXT: movl {{[-0-9]+}}(%e{{[sb]}}p), %ebx # 4-byte Reload
+; X86-NEXT: shldl %cl, %ebx, %eax
+; X86-NEXT: movl 8(%ebp), %ecx
+; X86-NEXT: xorl 12(%ecx), %esi
+; X86-NEXT: xorl 8(%ecx), %edx
+; X86-NEXT: xorl 4(%ecx), %eax
+; X86-NEXT: xorl (%ecx), %edi
+; X86-NEXT: movl %edx, 8(%ecx)
+; X86-NEXT: movl %esi, 12(%ecx)
+; X86-NEXT: movl %edi, (%ecx)
+; X86-NEXT: movl %eax, 4(%ecx)
+; X86-NEXT: orl %esi, %eax
+; X86-NEXT: orl %edx, %edi
+; X86-NEXT: orl %eax, %edi
+; X86-NEXT: setne %al
+; X86-NEXT: leal -12(%ebp), %esp
+; X86-NEXT: popl %esi
+; X86-NEXT: popl %edi
+; X86-NEXT: popl %ebx
+; X86-NEXT: popl %ebp
+; X86-NEXT: retl
+;
+; SSE-LABEL: complement_cmpz_i128:
+; SSE: # %bb.0:
+; SSE-NEXT: movl %esi, %ecx
+; SSE-NEXT: movl $1, %eax
+; SSE-NEXT: xorl %edx, %edx
+; SSE-NEXT: shldq %cl, %rax, %rdx
+; SSE-NEXT: shlq %cl, %rax
+; SSE-NEXT: xorl %esi, %esi
+; SSE-NEXT: testb $64, %cl
+; SSE-NEXT: cmovneq %rax, %rdx
+; SSE-NEXT: cmovneq %rsi, %rax
+; SSE-NEXT: xorq 8(%rdi), %rdx
+; SSE-NEXT: xorq (%rdi), %rax
+; SSE-NEXT: movq %rax, (%rdi)
+; SSE-NEXT: movq %rdx, 8(%rdi)
+; SSE-NEXT: orq %rdx, %rax
+; SSE-NEXT: setne %al
+; SSE-NEXT: retq
+;
+; AVX2-LABEL: complement_cmpz_i128:
+; AVX2: # %bb.0:
+; AVX2-NEXT: movl %esi, %ecx
+; AVX2-NEXT: movl $1, %eax
+; AVX2-NEXT: xorl %edx, %edx
+; AVX2-NEXT: shldq %cl, %rax, %rdx
+; AVX2-NEXT: xorl %esi, %esi
+; AVX2-NEXT: shlxq %rcx, %rax, %rax
+; AVX2-NEXT: testb $64, %cl
+; AVX2-NEXT: cmovneq %rax, %rdx
+; AVX2-NEXT: cmovneq %rsi, %rax
+; AVX2-NEXT: xorq 8(%rdi), %rdx
+; AVX2-NEXT: xorq (%rdi), %rax
+; AVX2-NEXT: movq %rax, (%rdi)
+; AVX2-NEXT: movq %rdx, 8(%rdi)
+; AVX2-NEXT: orq %rdx, %rax
+; AVX2-NEXT: setne %al
+; AVX2-NEXT: retq
+;
+; AVX512-LABEL: complement_cmpz_i128:
+; AVX512: # %bb.0:
+; AVX512-NEXT: movl %esi, %ecx
+; AVX512-NEXT: xorl %eax, %eax
+; AVX512-NEXT: movl $1, %edx
+; AVX512-NEXT: xorl %esi, %esi
+; AVX512-NEXT: shldq %cl, %rdx, %rsi
+; AVX512-NEXT: shlxq %rcx, %rdx, %rdx
+; AVX512-NEXT: testb $64, %cl
+; AVX512-NEXT: cmovneq %rdx, %rsi
+; AVX512-NEXT: cmovneq %rax, %rdx
+; AVX512-NEXT: xorq 8(%rdi), %rsi
+; AVX512-NEXT: xorq (%rdi), %rdx
+; AVX512-NEXT: movq %rdx, (%rdi)
+; AVX512-NEXT: movq %rsi, 8(%rdi)
+; AVX512-NEXT: orq %rsi, %rdx
+; AVX512-NEXT: setne %al
+; AVX512-NEXT: retq
+ %rem = and i32 %position, 127
+ %ofs = zext nneg i32 %rem to i128
+ %bit = shl nuw i128 1, %ofs
+ %ld = load i128, ptr %word
+ %res = xor i128 %ld, %bit
+ store i128 %res, ptr %word
+ %cmp = icmp ne i128 %res, 0
+ ret i1 %cmp
+}
+
+; Multiple loads in store chain
+define i32 @reset_multiload_i128(ptr %word, i32 %position, ptr %p) nounwind {
+; X86-LABEL: reset_multiload_i128:
+; X86: # %bb.0:
+; X86-NEXT: pushl %ebp
+; X86-NEXT: movl %esp, %ebp
+; X86-NEXT: pushl %ebx
+; X86-NEXT: pushl %edi
+; X86-NEXT: pushl %esi
+; X86-NEXT: andl $-16, %esp
+; X86-NEXT: subl $64, %esp
+; X86-NEXT: movl 12(%ebp), %ecx
+; X86-NEXT: movl $0, {{[0-9]+}}(%esp)
+; X86-NEXT: movl $0, {{[0-9]+}}(%esp)
+; X86-NEXT: movl $0, {{[0-9]+}}(%esp)
+; X86-NEXT: movl $1, {{[0-9]+}}(%esp)
+; X86-NEXT: movl $0, {{[0-9]+}}(%esp)
+; X86-NEXT: movl $0, {{[0-9]+}}(%esp)
+; X86-NEXT: movl $0, {{[0-9]+}}(%esp)
+; X86-NEXT: movl $0, {{[0-9]+}}(%esp)
+; X86-NEXT: movl %ecx, %eax
+; X86-NEXT: shrb $3, %al
+; X86-NEXT: andb $12, %al
+; X86-NEXT: negb %al
+; X86-NEXT: movsbl %al, %edi
+; X86-NEXT: movl 36(%esp,%edi), %edx
+; X86-NEXT: movl 40(%esp,%edi), %ebx
+; X86-NEXT: movl %ebx, %esi
+; X86-NEXT: shldl %cl, %edx, %esi
+; X86-NEXT: movl 32(%esp,%edi), %eax
+; X86-NEXT: movl %eax, {{[-0-9]+}}(%e{{[sb]}}p) # 4-byte Spill
+; X86-NEXT: movl 44(%esp,%edi), %edi
+; X86-NEXT: shldl %cl, %ebx, %edi
+; X86-NEXT: movl %eax, %ebx
+; X86-NEXT: # kill: def $cl killed $cl killed $ecx
+; X86-NEXT: shll %cl, %ebx
+; X86-NEXT: notl %ebx
+; X86-NEXT: movl 16(%ebp), %eax
+; X86-NEXT: movl (%eax), %eax
+; X86-NEXT: movl %eax, {{[-0-9]+}}(%e{{[sb]}}p) # 4-byte Spill
+; X86-NEXT: movl 12(%ebp), %eax
+; X86-NEXT: andl $96, %eax
+; X86-NEXT: shrl $3, %eax
+; X86-NEXT: movl 8(%ebp), %ecx
+; X86-NEXT: movl (%ecx,%eax), %eax
+; X86-NEXT: andl %ebx, (%ecx)
+; X86-NEXT: movl 12(%ebp), %ecx
+; X86-NEXT: movl {{[-0-9]+}}(%e{{[sb]}}p), %ebx # 4-byte Reload
+; X86-NEXT: shldl %cl, %ebx, %edx
+; X86-NEXT: notl %edx
+; X86-NEXT: movl 8(%ebp), %ebx
+; X86-NEXT: andl %edx, 4(%ebx)
+; X86-NEXT: notl %esi
+; X86-NEXT: andl %esi, 8(%ebx)
+; X86-NEXT: notl %edi
+; X86-NEXT: andl %edi, 12(%ebx)
+; X86-NEXT: btl %ecx, %eax
+; X86-NEXT: movl {{[-0-9]+}}(%e{{[sb]}}p), %eax # 4-byte Reload
+; X86-NEXT: jae .LBB22_2
+; X86-NEXT: # %bb.1:
+; X86-NEXT: xorl %eax, %eax
+; X86-NEXT: .LBB22_2:
+; X86-NEXT: leal -12(%ebp), %esp
+; X86-NEXT: popl %esi
+; X86-NEXT: popl %edi
+; X86-NEXT: popl %ebx
+; X86-NEXT: popl %ebp
+; X86-NEXT: retl
+;
+; SSE-LABEL: reset_multiload_i128:
+; SSE: # %bb.0:
+; SSE-NEXT: movl %esi, %ecx
+; SSE-NEXT: movl $1, %esi
+; SSE-NEXT: xorl %r8d, %r8d
+; SSE-NEXT: shldq %cl, %rsi, %r8
+; SSE-NEXT: xorl %eax, %eax
+; SSE-NEXT: shlq %cl, %rsi
+; SSE-NEXT: testb $64, %cl
+; SSE-NEXT: cmovneq %rsi, %r8
+; SSE-NEXT: cmovneq %rax, %rsi
+; SSE-NEXT: notq %r8
+; SSE-NEXT: notq %rsi
+; SSE-NEXT: movl %ecx, %r9d
+; SSE-NEXT: andl $96, %r9d
+; SSE-NEXT: shrl $3, %r9d
+; SSE-NEXT: movl (%rdi,%r9), %r9d
+; SSE-NEXT: btl %ecx, %r9d
+; SSE-NEXT: jb .LBB22_2
+; SSE-NEXT: # %bb.1:
+; SSE-NEXT: movl (%rdx), %eax
+; SSE-NEXT: .LBB22_2:
+; SSE-NEXT: andq %r8, 8(%rdi)
+; SSE-NEXT: andq %rsi, (%rdi)
+; SSE-NEXT: # kill: def $eax killed $eax killed $rax
+; SSE-NEXT: retq
+;
+; AVX2-LABEL: reset_multiload_i128:
+; AVX2: # %bb.0:
+; AVX2-NEXT: movl %esi, %ecx
+; AVX2-NEXT: xorl %eax, %eax
+; AVX2-NEXT: movl $1, %r8d
+; AVX2-NEXT: xorl %esi, %esi
+; AVX2-NEXT: shldq %cl, %r8, %rsi
+; AVX2-NEXT: shlxq %rcx, %r8, %r8
+; AVX2-NEXT: testb $64, %cl
+; AVX2-NEXT: cmovneq %r8, %rsi
+; AVX2-NEXT: cmovneq %rax, %r8
+; AVX2-NEXT: notq %rsi
+; AVX2-NEXT: notq %r8
+; AVX2-NEXT: movl %ecx, %r9d
+; AVX2-NEXT: andl $96, %r9d
+; AVX2-NEXT: shrl $3, %r9d
+; AVX2-NEXT: movl (%rdi,%r9), %r9d
+; AVX2-NEXT: btl %ecx, %r9d
+; AVX2-NEXT: jb .LBB22_2
+; AVX2-NEXT: # %bb.1:
+; AVX2-NEXT: movl (%rdx), %eax
+; AVX2-NEXT: .LBB22_2:
+; AVX2-NEXT: andq %rsi, 8(%rdi)
+; AVX2-NEXT: andq %r8, (%rdi)
+; AVX2-NEXT: # kill: def $eax killed $eax killed $rax
+; AVX2-NEXT: retq
+;
+; AVX512-LABEL: reset_multiload_i128:
+; AVX512: # %bb.0:
+; AVX512-NEXT: movl %esi, %ecx
+; AVX512-NEXT: movl $1, %r8d
+; AVX512-NEXT: xorl %esi, %esi
+; AVX512-NEXT: shldq %cl, %r8, %rsi
+; AVX512-NEXT: xorl %eax, %eax
+; AVX512-NEXT: shlxq %rcx, %r8, %r8
+; AVX512-NEXT: testb $64, %cl
+; AVX512-NEXT: cmovneq %r8, %rsi
+; AVX512-NEXT: cmovneq %rax, %r8
+; AVX512-NEXT: notq %rsi
+; AVX512-NEXT: notq %r8
+; AVX512-NEXT: movl %ecx, %r9d
+; AVX512-NEXT: andl $96, %r9d
+; AVX512-NEXT: shrl $3, %r9d
+; AVX512-NEXT: movl (%rdi,%r9), %r9d
+; AVX512-NEXT: btl %ecx, %r9d
+; AVX512-NEXT: jb .LBB22_2
+; AVX512-NEXT: # %bb.1:
+; AVX512-NEXT: movl (%rdx), %eax
+; AVX512-NEXT: .LBB22_2:
+; AVX512-NEXT: andq %rsi, 8(%rdi)
+; AVX512-NEXT: andq %r8, (%rdi)
+; AVX512-NEXT: # kill: def $eax killed $eax killed $rax
+; AVX512-NEXT: retq
+ %rem = and i32 %position, 127
+ %ofs = zext nneg i32 %rem to i128
+ %bit = shl nuw i128 1, %ofs
+ %mask = xor i128 %bit, -1
+ %ld = load i128, ptr %word
+ %sel = load i32, ptr %p
+ %test = and i128 %ld, %bit
+ %res = and i128 %ld, %mask
+ %cmp = icmp eq i128 %test, 0
+ store i128 %res, ptr %word
+ %ret = select i1 %cmp, i32 %sel, i32 0
+ ret i32 %ret
+}
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