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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@26924 91177308-0d34-0410-b5e6-96231b3b80d8
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Nate Begeman 2006-03-21 18:58:20 +00:00
parent 4d2182a729
commit c0a8b6df2a
1 changed files with 34 additions and 0 deletions
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34
lib/Target/PowerPC/README.txt
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@ -549,3 +549,37 @@ We need to codegen -0.0 vector efficiently (no constant pool load).
When -ffast-math is on, we can use 0.0.
===-------------------------------------------------------------------------===
float foo(float X) { return (int)(X); }
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
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
Note: this would speed up SingleSource/Misc/pi by about 30%