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llvm-mirror/test/CodeGen/X86/conditional-indecrement.ll
Benjamin Kramer 369872edfc Add some x86 specific dagcombines for conditional increments.
(add Y, (sete  X, 0)) -> cmp X, 1; adc  0, Y
(add Y, (setne X, 0)) -> cmp X, 1; sbb -1, Y
(sub (sete  X, 0), Y) -> cmp X, 1; sbb  0, Y
(sub (setne X, 0), Y) -> cmp X, 1; adc -1, Y

for
  unsigned foo(unsigned a, unsigned b) {
    if (a == 0) b++;
    return b;
  }
we now get:
  foo:
    cmpl  $1, %edi
    movl  %esi, %eax
    adcl  $0, %eax
    ret
instead of:
  foo:
    testl %edi, %edi
    sete  %al
    movzbl  %al, %eax
    addl  %esi, %eax
    ret

llvm-svn: 122364
2010-12-21 21:41:44 +00:00

90 lines
1.8 KiB
LLVM

; RUN: llc -march=x86 < %s | FileCheck %s
define i32 @test1(i32 %a, i32 %b) nounwind readnone {
%not.cmp = icmp ne i32 %a, 0
%inc = zext i1 %not.cmp to i32
%retval.0 = add i32 %inc, %b
ret i32 %retval.0
; CHECK: test1:
; CHECK: cmpl $1
; CHECK: sbbl $-1
; CHECK: ret
}
define i32 @test2(i32 %a, i32 %b) nounwind readnone {
%cmp = icmp eq i32 %a, 0
%inc = zext i1 %cmp to i32
%retval.0 = add i32 %inc, %b
ret i32 %retval.0
; CHECK: test2:
; CHECK: cmpl $1
; CHECK: adcl $0
; CHECK: ret
}
define i32 @test3(i32 %a, i32 %b) nounwind readnone {
%cmp = icmp eq i32 %a, 0
%inc = zext i1 %cmp to i32
%retval.0 = add i32 %inc, %b
ret i32 %retval.0
; CHECK: test3:
; CHECK: cmpl $1
; CHECK: adcl $0
; CHECK: ret
}
define i32 @test4(i32 %a, i32 %b) nounwind readnone {
%not.cmp = icmp ne i32 %a, 0
%inc = zext i1 %not.cmp to i32
%retval.0 = add i32 %inc, %b
ret i32 %retval.0
; CHECK: test4:
; CHECK: cmpl $1
; CHECK: sbbl $-1
; CHECK: ret
}
define i32 @test5(i32 %a, i32 %b) nounwind readnone {
%not.cmp = icmp ne i32 %a, 0
%inc = zext i1 %not.cmp to i32
%retval.0 = sub i32 %b, %inc
ret i32 %retval.0
; CHECK: test5:
; CHECK: cmpl $1
; CHECK: adcl $-1
; CHECK: ret
}
define i32 @test6(i32 %a, i32 %b) nounwind readnone {
%cmp = icmp eq i32 %a, 0
%inc = zext i1 %cmp to i32
%retval.0 = sub i32 %b, %inc
ret i32 %retval.0
; CHECK: test6:
; CHECK: cmpl $1
; CHECK: sbbl $0
; CHECK: ret
}
define i32 @test7(i32 %a, i32 %b) nounwind readnone {
%cmp = icmp eq i32 %a, 0
%inc = zext i1 %cmp to i32
%retval.0 = sub i32 %b, %inc
ret i32 %retval.0
; CHECK: test7:
; CHECK: cmpl $1
; CHECK: sbbl $0
; CHECK: ret
}
define i32 @test8(i32 %a, i32 %b) nounwind readnone {
%not.cmp = icmp ne i32 %a, 0
%inc = zext i1 %not.cmp to i32
%retval.0 = sub i32 %b, %inc
ret i32 %retval.0
; CHECK: test8:
; CHECK: cmpl $1
; CHECK: adcl $-1
; CHECK: ret
}