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llvm-mirror/test/CodeGen/X86/cmov.ll
Jakob Stoklund Olesen ef8527b836 Pseudo CMOV instructions don't clobber EFLAGS.
The explanation about a 0 argument being materialized as xor is no
longer valid.  Rematerialization will check if EFLAGS is live before
clobbering it.

The code produced by X86TargetLowering::EmitLoweredSelect does not
clobber EFLAGS.

This causes one less testb instruction to be generated in the cmov.ll
test case.

llvm-svn: 139057
2011-09-02 23:52:55 +00:00

158 lines
5.1 KiB
LLVM

; RUN: llc < %s -mtriple=x86_64-apple-darwin10 | FileCheck %s
target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128"
define i32 @test1(i32 %x, i32 %n, i32 %w, i32* %vp) nounwind readnone {
entry:
; CHECK: test1:
; CHECK: btl
; CHECK-NEXT: movl $12, %eax
; CHECK-NEXT: cmovael (%rcx), %eax
; CHECK-NEXT: ret
%0 = lshr i32 %x, %n ; <i32> [#uses=1]
%1 = and i32 %0, 1 ; <i32> [#uses=1]
%toBool = icmp eq i32 %1, 0 ; <i1> [#uses=1]
%v = load i32* %vp
%.0 = select i1 %toBool, i32 %v, i32 12 ; <i32> [#uses=1]
ret i32 %.0
}
define i32 @test2(i32 %x, i32 %n, i32 %w, i32* %vp) nounwind readnone {
entry:
; CHECK: test2:
; CHECK: btl
; CHECK-NEXT: movl $12, %eax
; CHECK-NEXT: cmovbl (%rcx), %eax
; CHECK-NEXT: ret
%0 = lshr i32 %x, %n ; <i32> [#uses=1]
%1 = and i32 %0, 1 ; <i32> [#uses=1]
%toBool = icmp eq i32 %1, 0 ; <i1> [#uses=1]
%v = load i32* %vp
%.0 = select i1 %toBool, i32 12, i32 %v ; <i32> [#uses=1]
ret i32 %.0
}
; x86's 32-bit cmov doesn't clobber the high 32 bits of the destination
; if the condition is false. An explicit zero-extend (movl) is needed
; after the cmov.
declare void @bar(i64) nounwind
define void @test3(i64 %a, i64 %b, i1 %p) nounwind {
; CHECK: test3:
; CHECK: cmovnel %edi, %esi
; CHECK-NEXT: movl %esi, %edi
%c = trunc i64 %a to i32
%d = trunc i64 %b to i32
%e = select i1 %p, i32 %c, i32 %d
%f = zext i32 %e to i64
call void @bar(i64 %f)
ret void
}
; CodeGen shouldn't try to do a setne after an expanded 8-bit conditional
; move without recomputing EFLAGS, because the expansion of the conditional
; move with control flow may clobber EFLAGS (e.g., with xor, to set the
; register to zero).
; The test is a little awkward; the important part is that there's a test before the
; setne.
; PR4814
@g_3 = external global i8 ; <i8*> [#uses=1]
@g_96 = external global i8 ; <i8*> [#uses=2]
@g_100 = external global i8 ; <i8*> [#uses=2]
@_2E_str = external constant [15 x i8], align 1 ; <[15 x i8]*> [#uses=1]
define i32 @test4() nounwind {
entry:
%0 = load i8* @g_3, align 1 ; <i8> [#uses=2]
%1 = sext i8 %0 to i32 ; <i32> [#uses=1]
%.lobit.i = lshr i8 %0, 7 ; <i8> [#uses=1]
%tmp.i = zext i8 %.lobit.i to i32 ; <i32> [#uses=1]
%tmp.not.i = xor i32 %tmp.i, 1 ; <i32> [#uses=1]
%iftmp.17.0.i.i = ashr i32 %1, %tmp.not.i ; <i32> [#uses=1]
%retval56.i.i = trunc i32 %iftmp.17.0.i.i to i8 ; <i8> [#uses=1]
%2 = icmp eq i8 %retval56.i.i, 0 ; <i1> [#uses=2]
%g_96.promoted.i = load i8* @g_96 ; <i8> [#uses=3]
%3 = icmp eq i8 %g_96.promoted.i, 0 ; <i1> [#uses=2]
br i1 %3, label %func_4.exit.i, label %bb.i.i.i
bb.i.i.i: ; preds = %entry
%4 = volatile load i8* @g_100, align 1 ; <i8> [#uses=0]
br label %func_4.exit.i
; CHECK: test4:
; CHECK: g_100
; CHECK: testb
; CHECK-NOT: xor
; CHECK: setne
; CHECK-NEXT: testb
func_4.exit.i: ; preds = %bb.i.i.i, %entry
%.not.i = xor i1 %2, true ; <i1> [#uses=1]
%brmerge.i = or i1 %3, %.not.i ; <i1> [#uses=1]
%.mux.i = select i1 %2, i8 %g_96.promoted.i, i8 0 ; <i8> [#uses=1]
br i1 %brmerge.i, label %func_1.exit, label %bb.i.i
bb.i.i: ; preds = %func_4.exit.i
%5 = volatile load i8* @g_100, align 1 ; <i8> [#uses=0]
br label %func_1.exit
func_1.exit: ; preds = %bb.i.i, %func_4.exit.i
%g_96.tmp.0.i = phi i8 [ %g_96.promoted.i, %bb.i.i ], [ %.mux.i, %func_4.exit.i ] ; <i8> [#uses=2]
store i8 %g_96.tmp.0.i, i8* @g_96
%6 = zext i8 %g_96.tmp.0.i to i32 ; <i32> [#uses=1]
%7 = tail call i32 (i8*, ...)* @printf(i8* noalias getelementptr ([15 x i8]* @_2E_str, i64 0, i64 0), i32 %6) nounwind ; <i32> [#uses=0]
ret i32 0
}
declare i32 @printf(i8* nocapture, ...) nounwind
; Should compile to setcc | -2.
; rdar://6668608
define i32 @test5(i32* nocapture %P) nounwind readonly {
entry:
; CHECK: test5:
; CHECK: setg %al
; CHECK: movzbl %al, %eax
; CHECK: orl $-2, %eax
; CHECK: ret
%0 = load i32* %P, align 4 ; <i32> [#uses=1]
%1 = icmp sgt i32 %0, 41 ; <i1> [#uses=1]
%iftmp.0.0 = select i1 %1, i32 -1, i32 -2 ; <i32> [#uses=1]
ret i32 %iftmp.0.0
}
define i32 @test6(i32* nocapture %P) nounwind readonly {
entry:
; CHECK: test6:
; CHECK: setl %al
; CHECK: movzbl %al, %eax
; CHECK: leal 4(%rax,%rax,8), %eax
; CHECK: ret
%0 = load i32* %P, align 4 ; <i32> [#uses=1]
%1 = icmp sgt i32 %0, 41 ; <i1> [#uses=1]
%iftmp.0.0 = select i1 %1, i32 4, i32 13 ; <i32> [#uses=1]
ret i32 %iftmp.0.0
}
; Don't try to use a 16-bit conditional move to do an 8-bit select,
; because it isn't worth it. Just use a branch instead.
define i8 @test7(i1 inreg %c, i8 inreg %a, i8 inreg %b) nounwind {
; CHECK: test7:
; CHECK: testb $1, %dil
; CHECK-NEXT: jne LBB
%d = select i1 %c, i8 %a, i8 %b
ret i8 %d
}