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* [gcc(refs/vendors/redhat/heads/gcc-8-branch)] cprop: Fix -fcompare-debug bug in constprop_register [PR100148]
@ 2021-05-14 14:56 Jakub Jelinek
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From: Jakub Jelinek @ 2021-05-14 14:56 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:0b5df85a952cac06c037e07b1f4668eda801862e
commit 0b5df85a952cac06c037e07b1f4668eda801862e
Author: Jakub Jelinek <jakub@redhat.com>
Date: Wed Apr 21 12:31:45 2021 +0200
cprop: Fix -fcompare-debug bug in constprop_register [PR100148]
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.
(cherry picked from commit 022f6ee3ad67ee30f62c8c2aeeb4156494f3284e)
Diff:
---
gcc/cprop.c | 8 +++++---
gcc/testsuite/g++.dg/opt/pr100148.C | 27 +++++++++++++++++++++++++++
2 files changed, 32 insertions(+), 3 deletions(-)
diff --git a/gcc/cprop.c b/gcc/cprop.c
index e4df5092144..a10791878f7 100644
--- a/gcc/cprop.c
+++ b/gcc/cprop.c
@@ -1008,16 +1008,18 @@ 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;
}
diff --git a/gcc/testsuite/g++.dg/opt/pr100148.C b/gcc/testsuite/g++.dg/opt/pr100148.C
new file mode 100644
index 00000000000..d038879b6b8
--- /dev/null
+++ b/gcc/testsuite/g++.dg/opt/pr100148.C
@@ -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 ());
+ }
+}
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