Changes in directory llvm/lib/Target/X86:
README.txt updated: 1.84 -> 1.85
---
Log message:
add a note
---
Diffs of the changes: (+23 -0)
README.txt | 23 +++++++++++++++++++++++
1 files changed, 23 insertions(+)
Index: llvm/lib/Target/X86/README.txt
diff -u llvm/lib/Target/X86/README.txt:1.84 llvm/lib/Target/X86/README.txt:1.85
--- llvm/lib/Target/X86/README.txt:1.84 Mon Apr 10 16:42:57 2006
+++ llvm/lib/Target/X86/README.txt Mon Apr 10 16:51:03 2006
@@ -675,6 +675,29 @@
//===---------------------------------------------------------------------===//
+Better codegen for:
+
+void f(float a, float b, vector float * out) { *out = (vector float){ a, 0.0,
0.0, b}; }
+void f(float a, float b, vector float * out) { *out = (vector float){ a, b,
0.0, 0}; }
+
+For the later we generate:
+
+_f:
+ pxor %xmm0, %xmm0
+ movss 8(%esp), %xmm1
+ movaps %xmm0, %xmm2
+ unpcklps %xmm1, %xmm2
+ movss 4(%esp), %xmm1
+ unpcklps %xmm0, %xmm1
+ unpcklps %xmm2, %xmm1
+ movl 12(%esp), %eax
+ movaps %xmm1, (%eax)
+ ret
+
+This seems like it should use shufps, one for each of a & b.
+
+//===---------------------------------------------------------------------===//
+
Adding to the list of cmp / test poor codegen issues:
int test(__m128 *A, __m128 *B) {
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