diff options
Diffstat (limited to 'llvm/lib/Target/PowerPC/README.txt')
| -rw-r--r-- | llvm/lib/Target/PowerPC/README.txt | 42 |
1 files changed, 6 insertions, 36 deletions
diff --git a/llvm/lib/Target/PowerPC/README.txt b/llvm/lib/Target/PowerPC/README.txt index 58805562a87..1ba89aa448a 100644 --- a/llvm/lib/Target/PowerPC/README.txt +++ b/llvm/lib/Target/PowerPC/README.txt @@ -3,10 +3,15 @@ TODO: * implement do-loop -> bdnz transform * implement powerpc-64 for darwin * use stfiwx in float->int -* be able to combine sequences like the following into 2 instructions: + +* Fold add and sub with constant into non-extern, non-weak addresses so this: lis r2, ha16(l2__ZTV4Cell) la r2, lo16(l2__ZTV4Cell)(r2) addi r2, r2, 8 +becomes: + lis r2, ha16(l2__ZTV4Cell+8) + la r2, lo16(l2__ZTV4Cell+8)(r2) + * Teach LLVM how to codegen this: unsigned short foo(float a) { return a; } @@ -24,10 +29,6 @@ _foo: rlwinm r3, r2, 0, 16, 31 blr -and: - extern int X, Y; int* test(int C) { return C? &X : &Y; } -as one load when using --enable-pic. - * Support 'update' load/store instructions. These are cracked on the G5, but are still a codesize win. @@ -170,37 +171,6 @@ things like this, rather than forcing llvm to generate the equivalent ===-------------------------------------------------------------------------=== -Compile this (standard bitfield insert of a constant): -void %test(uint* %tmp1) { - %tmp2 = load uint* %tmp1 ; <uint> [#uses=1] - %tmp5 = or uint %tmp2, 257949696 ; <uint> [#uses=1] - %tmp6 = and uint %tmp5, 4018143231 ; <uint> [#uses=1] - store uint %tmp6, uint* %tmp1 - ret void -} - -to: - -_test: - lwz r0,0(r3) - li r2,123 - rlwimi r0,r2,21,3,10 - stw r0,0(r3) - blr - -instead of: - -_test: - lis r2, -4225 - lwz r4, 0(r3) - ori r2, r2, 65535 - oris r4, r4, 3936 - and r2, r4, r2 - stw r2, 0(r3) - blr - -===-------------------------------------------------------------------------=== - Compile this: int %f1(int %a, int %b) { |
