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this is an SSE-specific issue.

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llvm-svn: 93373
This commit is contained in:
Chris Lattner 2010-01-13 23:29:11 +00:00
parent 0aa093dbdf
commit 72a06499b3
2 changed files with 20 additions and 20 deletions
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20
lib/Target/X86/README-SSE.txt
View File

@ -916,3 +916,23 @@ cheaper to do fld1 than load from a constant pool for example, so
"load, add 1.0, store" is better done in the fp stack, etc.
//===---------------------------------------------------------------------===//
The X86 backend should be able to if-convert SSE comparisons like "ucomisd" to
"cmpsd". For example, this code:
double d1(double x) { return x == x ? x : x + x; }
Compiles into:
_d1:
ucomisd %xmm0, %xmm0
jnp LBB1_2
addsd %xmm0, %xmm0
ret
LBB1_2:
ret
Also, the 'ret's should be shared. This is PR6032.
//===---------------------------------------------------------------------===//

20
lib/Target/X86/README.txt
View File

@ -1868,23 +1868,3 @@ carried over to machine instructions. Asm printer (or JIT) can use this
information to add the "lock" prefix.
//===---------------------------------------------------------------------===//
The X86 backend should be able to if-convert SSE comparisons like "ucomisd" to
"cmpsd". For example, this code:
double d1(double x) { return x == x ? x : x + x; }
Compiles into:
_d1:
ucomisd %xmm0, %xmm0
jnp LBB1_2
addsd %xmm0, %xmm0
ret
LBB1_2:
ret
Also, the 'ret's should be shared. This is PR6032.
//===---------------------------------------------------------------------===//