Changes in directory llvm/lib/Target/X86:
README.txt updated: 1.33 -> 1.34
---
Log message:
Remove entries on fabs and fneg. These are done.
---
Diffs of the changes: (+0 -49)
README.txt | 49 -------------------------------------------------
1 files changed, 49 deletions(-)
Index: llvm/lib/Target/X86/README.txt
diff -u llvm/lib/Target/X86/README.txt:1.33 llvm/lib/Target/X86/README.txt:1.34
--- llvm/lib/Target/X86/README.txt:1.33 Mon Jan 30 20:10:06 2006
+++ llvm/lib/Target/X86/README.txt Tue Jan 31 16:26:21 2006
@@ -215,53 +215,6 @@
//===---------------------------------------------------------------------===//
-The code generated for 'abs' is truly aweful:
-
-float %foo(float %tmp.38) {
- %tmp.39 = setgt float %tmp.38, 0.000000e+00
- %tmp.45 = sub float -0.000000e+00, %tmp.38
- %mem_tmp.0.0 = select bool %tmp.39, float %tmp.38, float %tmp.45
- ret float %mem_tmp.0.0
-}
-
-_foo:
- subl $4, %esp
- movss LCPI1_0, %xmm0
- movss 8(%esp), %xmm1
- subss %xmm1, %xmm0
- xorps %xmm2, %xmm2
- ucomiss %xmm2, %xmm1
- setp %al
- seta %cl
- orb %cl, %al
- testb %al, %al
- jne LBB_foo_2 #
-LBB_foo_1: #
- movss %xmm0, %xmm1
-LBB_foo_2: #
- movss %xmm1, (%esp)
- flds (%esp)
- addl $4, %esp
- ret
-
-This should be a high-priority to fix. With the fp-stack, this is a single
-instruction. With SSE it could be far better than this. Why is the sequence
-above using 'setp'? It shouldn't care about nan's.
-
-//===---------------------------------------------------------------------===//
-
-Is there a better way to implement Y = -X (fneg) than the literal code:
-
-float %test(float %X) {
- %Y = sub float -0.0, %X
- ret float %Y
-}
-
- movss LCPI1_0, %xmm0 ;; load -0.0
- subss 8(%esp), %xmm0 ;; subtract
-
-//===---------------------------------------------------------------------===//
-
None of the SSE instructions are handled in X86RegisterInfo::foldMemoryOperand,
which prevents the spiller from folding spill code into the instructions.
@@ -358,5 +311,3 @@
This is bad for register pressure, though the dag isel is producing a
better schedule. :)
-
-
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