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5a6bace3ab
llvm-6502/lib/CodeGen/SelectionDAG
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Chris Lattner 5a6bace3ab If a target zero or sign extends the result of its setcc, allow folding of 
this into sign/zero extension instructions later.

On PPC, for example, this testcase:

%G = external global sbyte
implementation
void %test(int %X, int %Y) {
  %C = setlt int %X, %Y
  %D = cast bool %C to sbyte
  store sbyte %D, sbyte* %G
  ret void
}

Now codegens to:

        cmpw cr0, r3, r4
        li r3, 1
        li r4, 0
        blt .LBB_test_2 ;
.LBB_test_1:    ;
        or r3, r4, r4
.LBB_test_2:    ;
        addis r2, r2, ha16(L_G$non_lazy_ptr-"L00000$pb")
        lwz r2, lo16(L_G$non_lazy_ptr-"L00000$pb")(r2)
        stb r3, 0(r2)

instead of:

        cmpw cr0, r3, r4
        li r3, 1
        li r4, 0
        blt .LBB_test_2 ;
.LBB_test_1:    ;
        or r3, r4, r4
.LBB_test_2:    ;
***     rlwinm r3, r3, 0, 31, 31
        addis r2, r2, ha16(L_G$non_lazy_ptr-"L00000$pb")
        lwz r2, lo16(L_G$non_lazy_ptr-"L00000$pb")(r2)
        stb r3, 0(r2)


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@21148 91177308-0d34-0410-b5e6-96231b3b80d8
2005-04-07 19:43:53 +00:00
..
LegalizeDAG.cpp Teach ExpandShift how to handle shifts by a constant. This allows targets 2005-04-06 21:13:14 +00:00
Makefile Change Library Names Not To Conflict With Others When Installed 2004-10-27 23:18:45 +00:00
SelectionDAG.cpp If a target zero or sign extends the result of its setcc, allow folding of 2005-04-07 19:43:53 +00:00
SelectionDAGISel.cpp transform fabs/fabsf calls into FABS nodes. 2005-04-02 05:26:53 +00:00
SelectionDAGPrinter.cpp Don't mash stuff together. 2005-01-16 07:28:31 +00:00
TargetLowering.cpp Add a hook to find out how the target handles shift amounts that are out of 2005-01-19 03:36:14 +00:00