Changes in directory llvm/lib/Target/PowerPC:
README.txt updated: 1.60 -> 1.61
---
Log message:
Remove some stuff that now works
---
Diffs of the changes: (+0 -53)
README.txt | 53 -----------------------------------------------------
1 files changed, 53 deletions(-)
Index: llvm/lib/Target/PowerPC/README.txt
diff -u llvm/lib/Target/PowerPC/README.txt:1.60
llvm/lib/Target/PowerPC/README.txt:1.61
--- llvm/lib/Target/PowerPC/README.txt:1.60 Fri Feb 3 16:06:45 2006
+++ llvm/lib/Target/PowerPC/README.txt Sat Feb 4 01:29:35 2006
@@ -198,59 +198,6 @@
===-------------------------------------------------------------------------===
-176.gcc contains a bunch of code like this (this occurs dozens of times):
-
-int %test(uint %mode.0.i.0) {
- %tmp.79 = cast uint %mode.0.i.0 to sbyte ; <sbyte> [#uses=1]
- %tmp.80 = cast sbyte %tmp.79 to int ; <int> [#uses=1]
- %tmp.81 = shl int %tmp.80, ubyte 16 ; <int> [#uses=1]
- %tmp.82 = and int %tmp.81, 16711680
- ret int %tmp.82
-}
-
-which we compile to:
-
-_test:
- extsb r2, r3
- rlwinm r3, r2, 16, 8, 15
- blr
-
-The extsb is obviously dead. This can be handled by a future thing like
-MaskedValueIsZero that checks to see if bits are ever demanded (in this case,
-the sign bits are never used, so we can fold the sext_inreg to nothing).
-
-I'm seeing code like this:
-
- srwi r3, r3, 16
- extsb r3, r3
- rlwimi r4, r3, 16, 8, 15
-
-in which the extsb is preventing the srwi from being nuked.
-
-===-------------------------------------------------------------------------===
-
-Another example that occurs is:
-
-uint %test(int %specbits.6.1) {
- %tmp.2540 = shr int %specbits.6.1, ubyte 11 ; <int> [#uses=1]
- %tmp.2541 = cast int %tmp.2540 to uint ; <uint> [#uses=1]
- %tmp.2542 = shl uint %tmp.2541, ubyte 13 ; <uint> [#uses=1]
- %tmp.2543 = and uint %tmp.2542, 8192 ; <uint> [#uses=1]
- ret uint %tmp.2543
-}
-
-which we codegen as:
-
-l1_test:
- srawi r2, r3, 11
- rlwinm r3, r2, 13, 18, 18
- blr
-
-the srawi can be nuked by turning the SAR into a logical SHR (the sext bits
are
-dead), which I think can then be folded into the rlwinm.
-
-===-------------------------------------------------------------------------===
-
Compile offsets from allocas:
int *%test() {
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