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one case handled, expanded another testcase inline. 

llvm-svn: 82427
This commit is contained in:
Chris Lattner 2009-09-21 02:53:57 +00:00
parent 1eefa9c427
commit 9858859fd6
1 changed files with 16 additions and 20 deletions
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36
llvm/lib/Target/README.txt
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@ -1268,6 +1268,8 @@ http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35287 [LPRE crit edge splitting]
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34677 (licm does this, LPRE crit edge)
llvm-gcc t2.c -S -o - -O0 -emit-llvm | llvm-as | opt -mem2reg -simplifycfg -gvn | llvm-dis
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16799 [BITCAST PHI TRANS]
//===---------------------------------------------------------------------===//
Type based alias analysis:
@ -1275,31 +1277,25 @@ http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14705
//===---------------------------------------------------------------------===//
When GVN/PRE finds a store of float* to a must aliases pointer when expecting
an int*, it should turn it into a bitcast. This is a nice generalization of
the SROA hack that would apply to other cases, e.g.:
int foo(int C, int *P, float X) {
if (C) {
bar();
*P = 42;
} else
*(float*)P = X;
return *P;
}
One example (that requires crazy phi translation) is:
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16799 [BITCAST PHI TRANS]
//===---------------------------------------------------------------------===//
A/B get pinned to the stack because we turn an if/then into a select instead
of PRE'ing the load/store. This may be fixable in instcombine:
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37892
struct X { int i; };
int foo (int x) {
struct X a;
struct X b;
struct X *p;
a.i = 1;
b.i = 2;
if (x)
p = &a;
else
p = &b;
return p->i;
}
//===---------------------------------------------------------------------===//
Interesting missed case because of control flow flattening (should be 2 loads):
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26629