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

cprop: Fix -fcompare-debug bug in constprop_register [PR100148]

Browse source 
The following testcase shows different behavior between -g and -g0
in constprop_register, if a flags register setter is separated
from a conditional jump using those flags with -g by a DEBUG_INSN.
As it uses just NEXT_INSN, for -g it will look at the DEBUG_INSN which is
not a conditional jump, while otherwise it would look at the conditional
jump and call cprop_jump.

2021-04-21  Jakub Jelinek  <jakub@redhat.com>

	PR rtl-optimization/100148
	* cprop.c (constprop_register): Use next_nondebug_insn instead of
	NEXT_INSN.

	* g++.dg/opt/pr100148.C: New test.
This commit is contained in:
Jakub Jelinek 2021-04-21 12:31:45 +02:00
parent 021607e12c
commit 022f6ee3ad
2 changed files with 32 additions and 3 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

8
gcc/cprop.c
View file

@ -1007,16 +1007,18 @@ static int
constprop_register (rtx from, rtx src, rtx_insn *insn)
{
rtx sset;
rtx_insn *next_insn;
/* Check for reg or cc0 setting instructions followed by
conditional branch instructions first. */
if ((sset = single_set (insn)) != NULL
&& NEXT_INSN (insn)
&& any_condjump_p (NEXT_INSN (insn)) && onlyjump_p (NEXT_INSN (insn)))
&& (next_insn = next_nondebug_insn (insn)) != NULL
&& any_condjump_p (next_insn)
&& onlyjump_p (next_insn))
{
rtx dest = SET_DEST (sset);
if ((REG_P (dest) || CC0_P (dest))
&& cprop_jump (BLOCK_FOR_INSN (insn), insn, NEXT_INSN (insn),
&& cprop_jump (BLOCK_FOR_INSN (insn), insn, next_insn,
from, src))
return 1;
}

27
gcc/testsuite/g++.dg/opt/pr100148.C Normal file
View file

@ -0,0 +1,27 @@
// PR rtl-optimization/100148
// { dg-do compile }
// { dg-options "-O2 -fno-dce -fno-tree-dce -fno-tree-dominator-opts -fno-tree-sink -fcompare-debug" }
int i;
enum E { } e, ee;
bool
baz (int)
{
return ee;
}
bool bar ();
bool a, b;
void
foo ()
{
switch (ee)
{
case 0:
e = E (a ? : i);
case 1:
!(b || baz (0) && bar ());
}
}