Changes in directory llvm/lib/Target:
README.txt updated: 1.9 -> 1.10
---
Log message:
add a note
---
Diffs of the changes: (+15 -0)
README.txt | 15 +++++++++++++++
1 files changed, 15 insertions(+)
Index: llvm/lib/Target/README.txt
diff -u llvm/lib/Target/README.txt:1.9 llvm/lib/Target/README.txt:1.10
--- llvm/lib/Target/README.txt:1.9 Thu Mar 2 16:34:38 2006
+++ llvm/lib/Target/README.txt Fri Mar 3 19:19:34 2006
@@ -86,3 +86,18 @@
into:
int f(int a, int b) { return a * (a + 2 * b) + b * b; }
to eliminate a multiply.
+
+//===---------------------------------------------------------------------===//
+
+On targets with expensive 64-bit multiply, we could LSR this:
+
+for (i = ...; ++i) {
+ x = 1ULL << i;
+
+into:
+ long long tmp = 1;
+ for (i = ...; ++i, tmp+=tmp)
+ x = tmp;
+
+This would be a win on ppc32, but not x86 or ppc64.
+
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