Changes in directory llvm/lib/Target/PowerPC:
README.txt updated: 1.78 -> 1.79
---
Log message:
This has been implemented. Tweak it into another note
---
Diffs of the changes: (+9 -23)
README.txt | 32 +++++++++-----------------------
1 files changed, 9 insertions(+), 23 deletions(-)
Index: llvm/lib/Target/PowerPC/README.txt
diff -u llvm/lib/Target/PowerPC/README.txt:1.78
llvm/lib/Target/PowerPC/README.txt:1.79
--- llvm/lib/Target/PowerPC/README.txt:1.78 Tue Mar 21 12:58:20 2006
+++ llvm/lib/Target/PowerPC/README.txt Tue Mar 21 23:33:23 2006
@@ -552,34 +552,20 @@
float foo(float X) { return (int)(X); }
-Currently produces
+Currently produces:
_foo:
- lis r2, ha16(LCPI1_0)
- lis r3, 17200
fctiwz f0, f1
stfd f0, -8(r1)
- lwz r4, -4(r1)
- xoris r4, r4, 32768
- stw r4, -12(r1)
- stw r3, -16(r1)
- lfs f0, lo16(LCPI1_0)(r2)
- lfd f1, -16(r1)
- fsub f0, f1, f0
+ lwz r2, -4(r1)
+ extsw r2, r2
+ std r2, -16(r1)
+ lfd f0, -16(r1)
+ fcfid f0, f0
frsp f1, f0
blr
-When we have ppc64 working properly, it could produce the nicer code:
-
-_foo:
- fctiwz f0, f1
- stfd f0, -8(r1)
- lwz r4, -4(r1)
- extsh r4, r4
- std r4, -16(r1)
- lfd f1, -16(r1)
- fcfid f0, f0
- frsp f0, f0
- blr
+We could use a target dag combine to turn the lwz/extsw into an lwa when the
+lwz has a single use. Since LWA is cracked anyway, this would be a codesize
+win only.
-Note: this would speed up SingleSource/Misc/pi by about 30%
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