Changes in directory llvm/lib/Target/PowerPC:
README.txt updated: 1.34 -> 1.35
---
Log message:
a bad case for bitfield insert
---
Diffs of the changes: (+34 -0)
README.txt | 34 ++++++++++++++++++++++++++++++++++
1 files changed, 34 insertions(+)
Index: llvm/lib/Target/PowerPC/README.txt
diff -u llvm/lib/Target/PowerPC/README.txt:1.34
llvm/lib/Target/PowerPC/README.txt:1.35
--- llvm/lib/Target/PowerPC/README.txt:1.34 Tue Oct 25 18:50:02 2005
+++ llvm/lib/Target/PowerPC/README.txt Thu Oct 27 19:20:45 2005
@@ -185,3 +185,37 @@
things like this, rather than forcing llvm to generate the equivalent
(shl (add bitfield, C2), C1) with some kind of mask.
+
+===-------------------------------------------------------------------------===
+
+Compile this (standard bitfield insert of a constant):
+void %test(uint* %tmp1) {
+ %tmp2 = load uint* %tmp1 ; <uint> [#uses=1]
+ %tmp5 = or uint %tmp2, 257949696 ; <uint> [#uses=1]
+ %tmp6 = and uint %tmp5, 4018143231 ; <uint> [#uses=1]
+ store uint %tmp6, uint* %tmp1
+ ret void
+}
+
+to:
+
+_test:
+ lwz r0,0(r3)
+ li r2,123
+ rlwimi r0,r2,21,3,10
+ stw r0,0(r3)
+ blr
+
+instead of:
+
+_test:
+ lis r2, -4225
+ lwz r4, 0(r3)
+ ori r2, r2, 65535
+ oris r4, r4, 3936
+ and r2, r4, r2
+ stw r2, 0(r3)
+ blr
+
+
+
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