[llvm] r225217 - [PowerPC] Remove old README.txt entry
Hal Finkel
hfinkel at anl.gov
Mon Jan 5 14:20:23 PST 2015
Author: hfinkel
Date: Mon Jan 5 16:20:22 2015
New Revision: 225217
URL: http://llvm.org/viewvc/llvm-project?rev=225217&view=rev
Log:
[PowerPC] Remove old README.txt entry
We no longer generate horrible code for the stated function:
void f(signed char *a, _Bool b, _Bool c) {
signed char t = 0;
if (b) t = *a;
if (c) *a = t;
}
for which we now generate:
.L.f:
andi. 5, 5, 1
cmpldi 1, 4, 0
li 5, 0
beq 1, .LBB0_2
lbz 5, 0(3)
.LBB0_2: # %if.end
bclr 4, 1, 0
stb 5, 0(3)
blr
so we don't need the README.txt entry.
Modified:
llvm/trunk/lib/Target/PowerPC/README.txt
Modified: llvm/trunk/lib/Target/PowerPC/README.txt
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/PowerPC/README.txt?rev=225217&r1=225216&r2=225217&view=diff
==============================================================================
--- llvm/trunk/lib/Target/PowerPC/README.txt (original)
+++ llvm/trunk/lib/Target/PowerPC/README.txt Mon Jan 5 16:20:22 2015
@@ -211,16 +211,6 @@ _foo:
===-------------------------------------------------------------------------===
-We generate really bad code for this:
-
-int f(signed char *a, _Bool b, _Bool c) {
- signed char t = 0;
- if (b) t = *a;
- if (c) *a = t;
-}
-
-===-------------------------------------------------------------------------===
-
On the G5, logical CR operations are more expensive in their three
address form: ops that read/write the same register are half as expensive as
those that read from two registers that are different from their destination.
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