llvm-6502/lib
Chris Lattner 75592e4137 Implement dynamic allocas correctly. In particular, because we were copying
directly out of R1 (without using a CopyFromReg, which uses a chain), multiple
allocas were getting CSE'd together, producing bogus code.  For this:

int %foo(bool %X, int %A, int %B) {
        br bool %X, label %T, label %F
F:
        %G = alloca int
        %H = alloca int
        store int %A, int* %G
        store int %B, int* %H
        %R = load int* %G
        ret int %R
T:
        ret int 0
}

We were generating:

_foo:
        stwu r1, -16(r1)
        stw r31, 4(r1)
        or r31, r1, r1
        stw r1, 12(r31)
        cmpwi cr0, r3, 0
        bne cr0, .LBB_foo_2     ; T
.LBB_foo_1:     ; F
        li r2, 16
        subf r2, r2, r1   ;; One alloca
        or r1, r2, r2
        or r3, r1, r1
        or r1, r2, r2
        or r2, r1, r1
        stw r4, 0(r3)
        stw r5, 0(r2)
        lwz r3, 0(r3)
        lwz r1, 12(r31)
        lwz r31, 4(r31)
        lwz r1, 0(r1)
        blr
.LBB_foo_2:     ; T
        li r3, 0
        lwz r1, 12(r31)
        lwz r31, 4(r31)
        lwz r1, 0(r1)
        blr

Now we generate:

_foo:
        stwu r1, -16(r1)
        stw r31, 4(r1)
        or r31, r1, r1
        stw r1, 12(r31)
        cmpwi cr0, r3, 0
        bne cr0, .LBB_foo_2     ; T
.LBB_foo_1:     ; F
        or r2, r1, r1
        li r3, 16
        subf r2, r3, r2  ;; Alloca 1
        or r1, r2, r2
        or r2, r1, r1
        or r6, r1, r1
        subf r3, r3, r6  ;; Alloca 2
        or r1, r3, r3
        or r3, r1, r1
        stw r4, 0(r2)
        stw r5, 0(r3)
        lwz r3, 0(r2)
        lwz r1, 12(r31)
        lwz r31, 4(r31)
        lwz r1, 0(r1)
        blr
.LBB_foo_2:     ; T
        li r3, 0
        lwz r1, 12(r31)
        lwz r31, 4(r31)
        lwz r1, 0(r1)
        blr

This fixes Povray and SPASS with the dag isel, the last two failing cases.
Tommorow we will hopefully turn it on by default! :)


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23190 91177308-0d34-0410-b5e6-96231b3b80d8
2005-09-01 21:31:30 +00:00
..
Analysis floor/ceil don't read/write memory. This allows gcse to eliminate 6 calls 2005-08-24 16:58:56 +00:00
Archive
AsmParser Implement PR614: 2005-08-27 18:50:39 +00:00
Bytecode
CodeGen It is NDEBUG not _NDEBUG 2005-09-01 18:44:10 +00:00
Debugger
ExecutionEngine
Linker
Support Allow bugpoint+PPC codegen to use fsqrt 2005-08-29 13:14:24 +00:00
System For PR616: 2005-08-24 10:07:20 +00:00
Target Implement dynamic allocas correctly. In particular, because we were copying 2005-09-01 21:31:30 +00:00
Transforms Fix Regression/Transforms/Reassociate/2005-08-24-Crash.ll 2005-08-24 17:55:32 +00:00
VMCore add printer support for flag operands 2005-08-25 17:59:23 +00:00
Makefile