llvm-6502/test/CodeGen/X86/const-select.ll
Chris Lattner d1980a5acd Move 3 "(add (select cc, 0, c), x) -> (select cc, x, (add, x, c))"
related transformations out of target-specific dag combine into the
ARM backend.  These were added by Evan in r37685 with no testcases
and only seems to help ARM (e.g. test/CodeGen/ARM/select_xform.ll).

Add some simple X86-specific (for now) DAG combines that turn things
like cond ? 8 : 0  -> (zext(cond) << 3).  This happens frequently
with the recently added cp constant select optimization, but is a
very general xform.  For example, we now compile the second example
in const-select.ll to:

_test:
        movsd   LCPI2_0, %xmm0
        ucomisd 8(%esp), %xmm0
        seta    %al
        movzbl  %al, %eax
        movl    4(%esp), %ecx
        movsbl  (%ecx,%eax,4), %eax
        ret

instead of:

_test:
        movl    4(%esp), %eax
        leal    4(%eax), %ecx
        movsd   LCPI2_0, %xmm0
        ucomisd 8(%esp), %xmm0
        cmovbe  %eax, %ecx
        movsbl  (%ecx), %eax
        ret

This passes multisource and dejagnu.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66779 91177308-0d34-0410-b5e6-96231b3b80d8
2009-03-12 06:52:53 +00:00

23 lines
820 B
LLVM

target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
target triple = "i386-apple-darwin7"
; RUN: llvm-as < %s | llc | grep {LCPI1_0(,%eax,4)}
define float @f(i32 %x) nounwind readnone {
entry:
%0 = icmp eq i32 %x, 0 ; <i1> [#uses=1]
%iftmp.0.0 = select i1 %0, float 4.200000e+01, float 2.300000e+01 ; <float> [#uses=1]
ret float %iftmp.0.0
}
; RUN: llvm-as < %s | llc | grep {movsbl.*(%e.x,%e.x,4), %eax}
define signext i8 @test(i8* nocapture %P, double %F) nounwind readonly {
entry:
%0 = fcmp olt double %F, 4.200000e+01 ; <i1> [#uses=1]
%iftmp.0.0 = select i1 %0, i32 4, i32 0 ; <i32> [#uses=1]
%1 = getelementptr i8* %P, i32 %iftmp.0.0 ; <i8*> [#uses=1]
%2 = load i8* %1, align 1 ; <i8> [#uses=1]
ret i8 %2
}