Changes in directory llvm/lib/Target/X86:
README.txt updated: 1.166 -> 1.167
---
Log message:
move CodeGen/X86/overlap-add.ll here.
---
Diffs of the changes: (+27 -0)
README.txt | 27 +++++++++++++++++++++++++++
1 files changed, 27 insertions(+)
Index: llvm/lib/Target/X86/README.txt
diff -u llvm/lib/Target/X86/README.txt:1.166
llvm/lib/Target/X86/README.txt:1.167
--- llvm/lib/Target/X86/README.txt:1.166 Mon Apr 16 19:02:37 2007
+++ llvm/lib/Target/X86/README.txt Sat May 5 17:10:24 2007
@@ -1004,6 +1004,33 @@
movl %edi, %eax
ret
+Another example is:
+
+;; X's live range extends beyond the shift, so the register allocator
+;; cannot coalesce it with Y. Because of this, a copy needs to be
+;; emitted before the shift to save the register value before it is
+;; clobbered. However, this copy is not needed if the register
+;; allocator turns the shift into an LEA. This also occurs for ADD.
+
+; Check that the shift gets turned into an LEA.
+; RUN: llvm-upgrade < %s | llvm-as | llc -march=x86 -x86-asm-syntax=intel | \
+; RUN: not grep {mov E.X, E.X}
+
+%G = external global int
+
+int %test1(int %X, int %Y) {
+ %Z = add int %X, %Y
+ volatile store int %Y, int* %G
+ volatile store int %Z, int* %G
+ ret int %X
+}
+
+int %test2(int %X) {
+ %Z = add int %X, 1 ;; inc
+ volatile store int %Z, int* %G
+ ret int %X
+}
+
//===---------------------------------------------------------------------===//
We use push/pop of stack space around calls in situations where we don't have
to.
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