[llvm-commits] CVS: llvm/lib/Target/PowerPC/README.txt

[Chris Lattner]

Changes in directory llvm/lib/Target/PowerPC:

README.txt updated: 1.104 -> 1.105
---
Log message:

add note about ugly codegen with preinc


---
Diffs of the changes:  (+29 -0)

 README.txt |   29 +++++++++++++++++++++++++++++
 1 files changed, 29 insertions(+)


Index: llvm/lib/Target/PowerPC/README.txt
diff -u llvm/lib/Target/PowerPC/README.txt:1.104 llvm/lib/Target/PowerPC/README.txt:1.105
--- llvm/lib/Target/PowerPC/README.txt:1.104	Tue Nov  7 12:30:21 2006
+++ llvm/lib/Target/PowerPC/README.txt	Thu Nov  9 19:33:53 2006
@@ -9,6 +9,35 @@
 Support 'update' load/store instructions.  These are cracked on the G5, but are
 still a codesize win.
 
+With preinc enabled, this:
+
+long *%test4(long *%X, long *%dest) {
+        %Y = getelementptr long* %X, int 4
+        %A = load long* %Y
+        store long %A, long* %dest
+        ret long* %Y
+}
+
+compiles to:
+
+_test4:
+        mr r2, r3
+        lwzu r5, 32(r2)
+        lwz r3, 36(r3)
+        stw r5, 0(r4)
+        stw r3, 4(r4)
+        mr r3, r2
+        blr 
+
+with -sched=list-burr, I get:
+
+_test4:
+        lwz r2, 36(r3)
+        lwzu r5, 32(r3)
+        stw r2, 4(r4)
+        stw r5, 0(r4)
+        blr 
+
 ===-------------------------------------------------------------------------===
 
 We compile the hottest inner loop of viterbi to: