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LLVM backend for 6502
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Chris Lattner f9186596f0 When processing outer loops and we find uses of an IV in inner loops, make 
sure to handle the use, just don't recurse into it.

This permits us to generate this code for a simple nested loop case:

.LBB_foo_0:     ; entry
        stwu r1, -48(r1)
        stw r29, 44(r1)
        stw r30, 40(r1)
        mflr r11
        stw r11, 56(r1)
        lis r2, ha16(L_A$non_lazy_ptr)
        lwz r30, lo16(L_A$non_lazy_ptr)(r2)
        li r29, 1
.LBB_foo_1:     ; no_exit.0
        bl L_bar$stub
        li r2, 1
        or r3, r30, r30
.LBB_foo_2:     ; no_exit.1
        lfd f0, 8(r3)
        stfd f0, 0(r3)
        addi r4, r2, 1
        addi r3, r3, 8
        cmpwi cr0, r2, 100
        or r2, r4, r4
        bne .LBB_foo_2  ; no_exit.1
.LBB_foo_3:     ; loopexit.1
        addi r30, r30, 800
        addi r2, r29, 1
        cmpwi cr0, r29, 100
        or r29, r2, r2
        bne .LBB_foo_1  ; no_exit.0
.LBB_foo_4:     ; return
        lwz r11, 56(r1)
        mtlr r11
        lwz r30, 40(r1)
        lwz r29, 44(r1)
        lwz r1, 0(r1)
        blr

instead of this:

_foo:
.LBB_foo_0:     ; entry
        stwu r1, -48(r1)
        stw r28, 44(r1)                   ;; uses an extra register.
        stw r29, 40(r1)
        stw r30, 36(r1)
        mflr r11
        stw r11, 56(r1)
        li r30, 1
        li r29, 0
        or r28, r29, r29
.LBB_foo_1:     ; no_exit.0
        bl L_bar$stub
        mulli r2, r28, 800           ;; unstrength-reduced multiply
        lis r3, ha16(L_A$non_lazy_ptr)   ;; loop invariant address computation
        lwz r3, lo16(L_A$non_lazy_ptr)(r3)
        add r2, r2, r3
        mulli r4, r29, 800           ;; unstrength-reduced multiply
        addi r3, r3, 8
        add r3, r4, r3
        li r4, 1
.LBB_foo_2:     ; no_exit.1
        lfd f0, 0(r3)
        stfd f0, 0(r2)
        addi r5, r4, 1
        addi r2, r2, 8                 ;; multiple stride 8 IV's
        addi r3, r3, 8
        cmpwi cr0, r4, 100
        or r4, r5, r5
        bne .LBB_foo_2  ; no_exit.1
.LBB_foo_3:     ; loopexit.1
        addi r28, r28, 1               ;;; Many IV's with stride 1
        addi r29, r29, 1
        addi r2, r30, 1
        cmpwi cr0, r30, 100
        or r30, r2, r2
        bne .LBB_foo_1  ; no_exit.0
.LBB_foo_4:     ; return
        lwz r11, 56(r1)
        mtlr r11
        lwz r30, 36(r1)
        lwz r29, 40(r1)
        lwz r28, 44(r1)
        lwz r1, 0(r1)
        blr


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@22640 91177308-0d34-0410-b5e6-96231b3b80d8
2005-08-04 00:14:11 +00:00
autoconf Fix PR608: 2005-07-27 21:58:38 +00:00
docs Update a doc, patch contributed by Jim Laskey! 2005-08-02 19:14:25 +00:00
examples Eliminate all remaining tabs and trailing spaces. 2005-07-27 06:12:32 +00:00
include/llvm Fix an obvious bug in the Log2 stuff that broke SingleSource/UnitTests/2005-05-12-Int64ToFP 2005-08-03 20:53:19 +00:00
lib When processing outer loops and we find uses of an IV in inner loops, make 2005-08-04 00:14:11 +00:00
projects oops 2005-07-05 16:36:18 +00:00
runtime Remove trailing whitespace 2005-04-21 23:48:37 +00:00
test this now passes 2005-08-03 22:51:40 +00:00
tools If the user interrupts bugpoint, don't extract loops 2005-08-02 23:25:56 +00:00
utils make is the standard name, not gmake 2005-08-02 00:10:52 +00:00
win32 Fix VC++ build problems. 2005-07-30 18:22:27 +00:00
.cvsignore Ignore the configure.out file generated by "make reconfigure" 2005-06-18 23:01:25 +00:00
configure Fix PR608: 2005-07-27 21:58:38 +00:00
CREDITS.TXT Add a note, people are responsible for requesting that they be added to the 2005-08-02 22:10:21 +00:00
LICENSE.TXT Remove extraneous colons after program names for consistency 2005-05-12 21:39:01 +00:00
llvm.spec Onward to LLVM-1.6 and beyond! 2005-05-18 20:23:20 +00:00
llvm.spec.in Onward to LLVM-1.6 and beyond! 2005-05-18 20:23:20 +00:00
Makefile Make sure the tools get built if no build target is specified. 2005-05-29 00:49:24 +00:00
Makefile.common
Makefile.config.in Two changes: 2005-04-22 17:14:14 +00:00
Makefile.rules No, really, it's an Alpha! And you probably thought it was a PowerPC. 2005-07-22 22:43:40 +00:00
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