mirror/gcc
2
0
Fork 0
mirror of git://gcc.gnu.org/git/gcc.git synced 2025-03-22 21:31:19 +08:00
Code Issues Packages Projects Releases Wiki Activity

tree-optimization/107935 - fixup equivalence handling in PHI VN

Browse Source 
The following makes sure to honor the backedge processing logic
that forces VARYING there.

	PR tree-optimization/107935
	* tree-ssa-sccvn.cc (visit_phi): Honor forced VARYING on
	backedges.

	* gcc.dg/torture/pr107935.c: New testcase.
This commit is contained in:
Richard Biener 2022-12-01 09:01:20 +01:00
parent 2c08964027
commit 8629f212af
2 changed files with 24 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
gcc/testsuite/gcc.dg/torture/pr107935.c Normal file
View File

@ -0,0 +1,18 @@
/* { dg-do compile } */
int *a, **b;
int main() {
int d = 0, *e = &d;
L:
*e = d;
if (a) {
int *g = e = *b;
if (!e)
__builtin_abort();
if (**b)
return 0;
*g = 1;
goto L;
}
return 0;
}

7
gcc/tree-ssa-sccvn.cc
View File

@ -5840,7 +5840,12 @@ visit_phi (gimple *phi, bool *inserted, bool backedges_varying_p)
continue;
}
/* There's also the possibility to use equivalences. */
if (!FLOAT_TYPE_P (TREE_TYPE (def)))
if (!FLOAT_TYPE_P (TREE_TYPE (def))
/* But only do this if we didn't force any of sameval or
val to VARYING because of backedge processing rules. */
&& (TREE_CODE (sameval) != SSA_NAME
|| SSA_VAL (sameval) == sameval)
&& (TREE_CODE (def) != SSA_NAME || SSA_VAL (def) == def))
{
vn_nary_op_t vnresult;
tree ops[2];