[x86] Clean up and enhance a test around eflags copying.
This adds the basic test cases from all the EFLAGS bugs in more direct forms. It also switches to generated check lines, and includes both 32-bit and 64-bit variations. No functionality changing here, just setting things up to have a nice clean asm diff in my EFLAGS patch. llvm-svn: 329056
This commit is contained in:
Chandler Carruth
parent
6646becd0c
commit
44a791a57a
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@ -1,6 +1,8 @@
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; RUN: llc -o - %s | FileCheck %s
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; This tests for the problem originally reported in http://llvm.org/PR25951
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target triple = "i686-unknown-linux-gnu"
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; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
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; RUN: llc -o - -mtriple=i686-unknown-unknown %s | FileCheck %s --check-prefixes=ALL,X32
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; RUN: llc -o - -mtriple=x86_64-unknown-unknown %s | FileCheck %s --check-prefixes=ALL,X64
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;
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; Test patterns that require preserving and restoring flags.
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@b = common global i8 0, align 1
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@c = common global i32 0, align 4
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@ -8,13 +10,75 @@ target triple = "i686-unknown-linux-gnu"
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@d = common global i8 0, align 1
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@.str = private unnamed_addr constant [4 x i8] c"%d\0A\00", align 1
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; CHECK-LABEL: func:
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; This tests whether eax is properly saved/restored around the
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; lahf/sahf instruction sequences. We make mem op volatile to prevent
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; their reordering to avoid spills.
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declare void @external(i32)
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define i32 @func() {
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; A test that re-uses flags in interesting ways due to volatile accesses.
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; Specifically, the first increment's flags are reused for the branch despite
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; being clobbered by the second increment.
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define i32 @test1() nounwind {
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; X32-LABEL: test1:
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; X32: # %bb.0: # %entry
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; X32-NEXT: movb b, %cl
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; X32-NEXT: movb %cl, %al
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; X32-NEXT: incb %al
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; X32-NEXT: movb %al, b
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; X32-NEXT: incl c
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; X32-NEXT: pushl %eax
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; X32-NEXT: seto %al
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; X32-NEXT: lahf
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; X32-NEXT: movl %eax, %edx
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; X32-NEXT: popl %eax
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; X32-NEXT: movb a, %ah
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; X32-NEXT: movb %ah, %ch
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; X32-NEXT: incb %ch
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; X32-NEXT: cmpb %cl, %ah
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; X32-NEXT: sete d
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; X32-NEXT: movb %ch, a
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; X32-NEXT: pushl %eax
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; X32-NEXT: movl %edx, %eax
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; X32-NEXT: addb $127, %al
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; X32-NEXT: sahf
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; X32-NEXT: popl %eax
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; X32-NEXT: je .LBB0_2
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; X32-NEXT: # %bb.1: # %if.then
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; X32-NEXT: pushl %ebp
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; X32-NEXT: movl %esp, %ebp
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; X32-NEXT: movsbl %al, %eax
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; X32-NEXT: pushl %eax
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; X32-NEXT: calll external
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; X32-NEXT: addl $4, %esp
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; X32-NEXT: popl %ebp
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; X32-NEXT: .LBB0_2: # %if.end
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; X32-NEXT: xorl %eax, %eax
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; X32-NEXT: retl
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;
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; X64-LABEL: test1:
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; X64: # %bb.0: # %entry
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; X64-NEXT: movb {{.*}}(%rip), %dil
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; X64-NEXT: movl %edi, %eax
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; X64-NEXT: incb %al
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; X64-NEXT: movb %al, {{.*}}(%rip)
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; X64-NEXT: incl {{.*}}(%rip)
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; X64-NEXT: pushfq
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; X64-NEXT: popq %rsi
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; X64-NEXT: movb {{.*}}(%rip), %cl
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; X64-NEXT: movl %ecx, %edx
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; X64-NEXT: incb %dl
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; X64-NEXT: cmpb %dil, %cl
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; X64-NEXT: sete {{.*}}(%rip)
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; X64-NEXT: movb %dl, {{.*}}(%rip)
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; X64-NEXT: pushq %rsi
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; X64-NEXT: popfq
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; X64-NEXT: je .LBB0_2
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; X64-NEXT: # %bb.1: # %if.then
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; X64-NEXT: pushq %rbp
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; X64-NEXT: movq %rsp, %rbp
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; X64-NEXT: movsbl %al, %edi
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; X64-NEXT: callq external
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; X64-NEXT: popq %rbp
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; X64-NEXT: .LBB0_2: # %if.end
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; X64-NEXT: xorl %eax, %eax
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; X64-NEXT: retq
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entry:
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%bval = load i8, i8* @b
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%inc = add i8 %bval, 1
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@ -25,33 +89,156 @@ entry:
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%aval = load volatile i8, i8* @a
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%inc2 = add i8 %aval, 1
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store volatile i8 %inc2, i8* @a
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; Copy flags produced by the incb of %inc1 to a register, need to save+restore
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; eax around it. The flags will be reused by %tobool.
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; CHECK: pushl %eax
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; CHECK: seto %al
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; CHECK: lahf
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; CHECK: movl %eax, [[REG:%[a-z]+]]
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; CHECK: popl %eax
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%cmp = icmp eq i8 %aval, %bval
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%conv5 = zext i1 %cmp to i8
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store i8 %conv5, i8* @d
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%tobool = icmp eq i32 %inc1, 0
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; We restore flags with an 'addb, sahf' sequence, need to save+restore eax
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; around it.
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; CHECK: pushl %eax
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; CHECK: movl [[REG]], %eax
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; CHECK: addb $127, %al
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; CHECK: sahf
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; CHECK: popl %eax
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br i1 %tobool, label %if.end, label %if.then
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if.then:
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%conv6 = sext i8 %inc to i32
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%call = tail call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str, i32 0, i32 0), i32 %conv6)
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call void @external(i32 %conv6)
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br label %if.end
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if.end:
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ret i32 0
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}
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declare i32 @printf(i8* nocapture readonly, ...)
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; Preserve increment flags across a call.
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define i32 @test2(i32* %ptr) nounwind {
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; X32-LABEL: test2:
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; X32: # %bb.0: # %entry
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; X32-NEXT: pushl %ebp
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; X32-NEXT: movl %esp, %ebp
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; X32-NEXT: pushl %esi
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; X32-NEXT: movl 8(%ebp), %eax
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; X32-NEXT: incl (%eax)
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; X32-NEXT: seto %al
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; X32-NEXT: lahf
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; X32-NEXT: movl %eax, %esi
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; X32-NEXT: pushl $42
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; X32-NEXT: calll external
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; X32-NEXT: addl $4, %esp
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; X32-NEXT: movl %esi, %eax
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; X32-NEXT: addb $127, %al
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; X32-NEXT: sahf
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; X32-NEXT: je .LBB1_1
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; X32-NEXT: # %bb.3: # %else
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; X32-NEXT: xorl %eax, %eax
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; X32-NEXT: jmp .LBB1_2
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; X32-NEXT: .LBB1_1: # %then
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; X32-NEXT: movl $64, %eax
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; X32-NEXT: .LBB1_2: # %then
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; X32-NEXT: popl %esi
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; X32-NEXT: popl %ebp
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; X32-NEXT: retl
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;
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; X64-LABEL: test2:
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; X64: # %bb.0: # %entry
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; X64-NEXT: pushq %rbp
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; X64-NEXT: movq %rsp, %rbp
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; X64-NEXT: pushq %rbx
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; X64-NEXT: pushq %rax
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; X64-NEXT: incl (%rdi)
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; X64-NEXT: pushfq
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; X64-NEXT: popq %rbx
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; X64-NEXT: movl $42, %edi
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; X64-NEXT: callq external
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; X64-NEXT: pushq %rbx
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; X64-NEXT: popfq
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; X64-NEXT: je .LBB1_1
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; X64-NEXT: # %bb.3: # %else
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; X64-NEXT: xorl %eax, %eax
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; X64-NEXT: jmp .LBB1_2
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; X64-NEXT: .LBB1_1: # %then
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; X64-NEXT: movl $64, %eax
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; X64-NEXT: .LBB1_2: # %then
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; X64-NEXT: addq $8, %rsp
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; X64-NEXT: popq %rbx
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; X64-NEXT: popq %rbp
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; X64-NEXT: retq
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entry:
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%val = load i32, i32* %ptr
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%inc = add i32 %val, 1
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store i32 %inc, i32* %ptr
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%cmp = icmp eq i32 %inc, 0
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call void @external(i32 42)
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br i1 %cmp, label %then, label %else
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then:
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ret i32 64
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else:
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ret i32 0
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}
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declare void @external_a()
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declare void @external_b()
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; This lowers to a conditional tail call instead of a conditional branch. This
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; is tricky because we can only do this from a leaf function, and so we have to
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; use volatile stores similar to test1 to force the save and restore of
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; a condition without calling another function. We then set up subsequent calls
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; in tail position.
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define void @test_tail_call(i32* %ptr) nounwind optsize {
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; X32-LABEL: test_tail_call:
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; X32: # %bb.0: # %entry
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; X32-NEXT: pushl %ebp
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; X32-NEXT: movl %esp, %ebp
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; X32-NEXT: movl 8(%ebp), %eax
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; X32-NEXT: incl (%eax)
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; X32-NEXT: seto %al
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; X32-NEXT: lahf
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; X32-NEXT: movl %eax, %eax
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; X32-NEXT: incb a
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; X32-NEXT: sete d
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; X32-NEXT: movl %eax, %eax
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; X32-NEXT: addb $127, %al
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; X32-NEXT: sahf
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; X32-NEXT: je .LBB2_1
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; X32-NEXT: # %bb.2: # %else
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; X32-NEXT: popl %ebp
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; X32-NEXT: jmp external_b # TAILCALL
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; X32-NEXT: .LBB2_1: # %then
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; X32-NEXT: popl %ebp
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; X32-NEXT: jmp external_a # TAILCALL
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;
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; X64-LABEL: test_tail_call:
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; X64: # %bb.0: # %entry
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; X64-NEXT: pushq %rbp
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; X64-NEXT: movq %rsp, %rbp
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; X64-NEXT: incl (%rdi)
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; X64-NEXT: pushfq
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; X64-NEXT: popq %rax
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; X64-NEXT: incb {{.*}}(%rip)
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; X64-NEXT: sete {{.*}}(%rip)
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; X64-NEXT: pushq %rax
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; X64-NEXT: popfq
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; X64-NEXT: je .LBB2_1
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; X64-NEXT: # %bb.2: # %else
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; X64-NEXT: popq %rbp
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; X64-NEXT: jmp external_b # TAILCALL
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; X64-NEXT: .LBB2_1: # %then
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; X64-NEXT: popq %rbp
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; X64-NEXT: jmp external_a # TAILCALL
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entry:
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%val = load i32, i32* %ptr
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%inc = add i32 %val, 1
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store i32 %inc, i32* %ptr
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%cmp = icmp eq i32 %inc, 0
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%aval = load volatile i8, i8* @a
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%inc2 = add i8 %aval, 1
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store volatile i8 %inc2, i8* @a
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%cmp2 = icmp eq i8 %inc2, 0
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%conv5 = zext i1 %cmp2 to i8
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store i8 %conv5, i8* @d
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br i1 %cmp, label %then, label %else
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then:
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tail call void @external_a()
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ret void
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else:
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tail call void @external_b()
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ret void
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}
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