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https://github.com/c64scene-ar/llvm-6502.git
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eee7a7a836
Lowering this new node allows us to fold the almost universal comparison for success before it's even formed. Instead we can create a copy from EFLAGS and an X86ISD::SETCC operation since all "cmpxchg" instructions set the zero-flag to the correct value. rdar://problem/13201607 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210923 91177308-0d34-0410-b5e6-96231b3b80d8
88 lines
2.2 KiB
LLVM
88 lines
2.2 KiB
LLVM
; RUN: llc -mtriple=x86_64 -o - %s | FileCheck %s
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define i1 @try_cmpxchg(i32* %addr, i32 %desired, i32 %new) {
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; CHECK-LABEL: try_cmpxchg:
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; CHECK: cmpxchgl
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; CHECK-NOT: cmp
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; CHECK: sete %al
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; CHECK: retq
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%pair = cmpxchg i32* %addr, i32 %desired, i32 %new seq_cst seq_cst
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%success = extractvalue { i32, i1 } %pair, 1
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ret i1 %success
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}
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define void @cmpxchg_flow(i64* %addr, i64 %desired, i64 %new) {
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; CHECK-LABEL: cmpxchg_flow:
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; CHECK: cmpxchgq
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; CHECK-NOT: cmp
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; CHECK-NOT: set
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; CHECK: {{jne|jeq}}
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%pair = cmpxchg i64* %addr, i64 %desired, i64 %new seq_cst seq_cst
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%success = extractvalue { i64, i1 } %pair, 1
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br i1 %success, label %true, label %false
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true:
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call void @foo()
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ret void
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false:
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call void @bar()
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ret void
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}
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define i64 @cmpxchg_sext(i32* %addr, i32 %desired, i32 %new) {
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; CHECK-LABEL: cmpxchg_sext:
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; CHECK-DAG: cmpxchgl
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; CHECK-NOT: cmpl
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; CHECK: sete %al
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; CHECK: retq
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%pair = cmpxchg i32* %addr, i32 %desired, i32 %new seq_cst seq_cst
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%success = extractvalue { i32, i1 } %pair, 1
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%mask = sext i1 %success to i64
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ret i64 %mask
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}
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define i32 @cmpxchg_zext(i32* %addr, i32 %desired, i32 %new) {
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; CHECK-LABEL: cmpxchg_zext:
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; CHECK: cmpxchgl
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; CHECK-NOT: cmp
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; CHECK: sete [[BYTE:%[a-z0-9]+]]
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; CHECK: movzbl [[BYTE]], %eax
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%pair = cmpxchg i32* %addr, i32 %desired, i32 %new seq_cst seq_cst
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%success = extractvalue { i32, i1 } %pair, 1
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%mask = zext i1 %success to i32
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ret i32 %mask
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}
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define i32 @cmpxchg_use_eflags_and_val(i32* %addr, i32 %offset) {
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; CHECK-LABEL: cmpxchg_use_eflags_and_val:
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; CHECK: movl (%rdi), %e[[OLDVAL:[a-z0-9]+]]
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; CHECK: [[LOOPBB:.?LBB[0-9]+_[0-9]+]]:
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; CHECK: leal (%r[[OLDVAL]],%rsi), [[NEW:%[a-z0-9]+]]
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; CHECK: cmpxchgl [[NEW]], (%rdi)
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; CHECK-NOT: cmpl
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; CHECK: jne [[LOOPBB]]
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; Result already in %eax
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; CHECK: retq
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entry:
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%init = load atomic i32* %addr seq_cst, align 4
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br label %loop
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loop:
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%old = phi i32 [%init, %entry], [%oldval, %loop]
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%new = add i32 %old, %offset
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%pair = cmpxchg i32* %addr, i32 %old, i32 %new seq_cst seq_cst
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%oldval = extractvalue { i32, i1 } %pair, 0
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%success = extractvalue { i32, i1 } %pair, 1
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br i1 %success, label %done, label %loop
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done:
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ret i32 %oldval
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}
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declare void @foo()
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declare void @bar()
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