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* [gcc(refs/users/ppalka/heads/integer_class_type)] Uninitialized padding in struct _dep.
@ 2020-01-16 20:36 Patrick Palka
0 siblings, 0 replies; only message in thread
From: Patrick Palka @ 2020-01-16 20:36 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:7c6056d52ef7ea43b503b11a571b316d55f392c7
commit 7c6056d52ef7ea43b503b11a571b316d55f392c7
Author: Andrew Pinski <apinski@marvell.com>
Date: Thu Jan 16 02:07:28 2020 +0000
Uninitialized padding in struct _dep.
In struct _dep, there is an implicit padding of 4bits. This
bit-field padding is uninitialized when init_dep_1 is being called.
This means we access uninitialized memory but never use it for
anything. Adding an unused bit-field field and initializing it
in init_dep_1 will improve code generation also as we initialize
the whole 32bits now rather than just part of it.
ChangeLog:
* sched-int.h (_dep): Add unused bit-field field for the padding.
* sched-deps.c (init_dep_1): Init unused field.
Diff:
---
gcc/ChangeLog | 5 +++++
gcc/sched-deps.c | 1 +
gcc/sched-int.h | 2 ++
3 files changed, 8 insertions(+)
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 4196998..bbb7e06 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,10 @@
2020-01-16 Andrew Pinski <apinski@marvell.com>
+ * sched-int.h (_dep): Add unused bit-field field for the padding.
+ * sched-deps.c (init_dep_1): Init unused field.
+
+2020-01-16 Andrew Pinski <apinski@marvell.com>
+
* optabs.h (create_expand_operand): Initialize target field also.
2020-01-16 Andre Vieira <andre.simoesdiasvieira@arm.com>
diff --git a/gcc/sched-deps.c b/gcc/sched-deps.c
index 9182aba..331af5f 100644
--- a/gcc/sched-deps.c
+++ b/gcc/sched-deps.c
@@ -101,6 +101,7 @@ init_dep_1 (dep_t dep, rtx_insn *pro, rtx_insn *con, enum reg_note type, ds_t ds
DEP_NONREG (dep) = 0;
DEP_MULTIPLE (dep) = 0;
DEP_REPLACE (dep) = NULL;
+ dep->unused = 0;
}
/* Init DEP with the arguments.
diff --git a/gcc/sched-int.h b/gcc/sched-int.h
index 833b552..a847f87 100644
--- a/gcc/sched-int.h
+++ b/gcc/sched-int.h
@@ -238,6 +238,8 @@ struct _dep
/* Cached cost of the dependency. Make sure to update UNKNOWN_DEP_COST
when changing the size of this field. */
int cost:20;
+
+ unsigned unused:4;
};
#define UNKNOWN_DEP_COST ((int) ((unsigned int) -1 << 19))
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