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[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.

llvm-svn: 225217
This commit is contained in:
Hal Finkel 2015-01-05 22:20:22 +00:00
parent 4c55af6850
commit 6837077fcf
1 changed files with 0 additions and 10 deletions
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10
llvm/lib/Target/PowerPC/README.txt
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@ -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.