procyberian/gcc
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

better PHI copy propagation for forwprop

Browse source 
We can handle _1 = PHI <_1, _2> as a copy.

	PR tree-optimization/84646
	* tree-ssa-forwprop.cc (pass_forwprop::execute): Improve
	copy propagation across PHIs.
This commit is contained in:
Richard Biener 2022-11-10 15:02:37 +01:00
parent 2f6cb9c51a
commit f1b76811f2
1 changed files with 6 additions and 1 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

7
gcc/tree-ssa-forwprop.cc
View file

@ -3384,7 +3384,12 @@ pass_forwprop::execute (function *fun)
FOR_EACH_PHI_ARG (use_p, phi, it, SSA_OP_USE)
{
tree use = USE_FROM_PTR (use_p);
if (! first)
if (use == res)
/* The PHI result can also appear on a backedge, if so
we can ignore this case for the purpose of determining
the singular value. */
;
else if (! first)
first = use;
else if (! operand_equal_p (first, use, 0))
{