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Fix handling of clobbers in ipa-modref.c

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* ipa-modref.c (analyze_stmt): Do not skip clobbers in early pass.
	* ipa-pure-const.c (analyze_stmt): Update comment.
This commit is contained in:
Jan Hubicka 2020-09-26 18:40:50 +02:00
parent 081b3517b4
commit 3991912e26
2 changed files with 9 additions and 4 deletions
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11
gcc/ipa-modref.c
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@ -676,13 +676,16 @@ static bool
analyze_stmt (modref_summary *summary, gimple *stmt, bool ipa,
vec <gimple *> *recursive_calls)
{
/* There is no need to record clobbers. */
if (gimple_clobber_p (stmt))
/* In general we can not ignore clobbers because they are barries for code
motion, however after inlining it is safe to do becuase local optimization
passes do not consider clobbers from other functions.
Similar logic is in ipa-pure-consts. */
if ((ipa || cfun->after_inlining) && gimple_clobber_p (stmt))
return true;
/* Analyze all loads and stores in STMT. */
walk_stmt_load_store_ops (stmt, summary,
analyze_load, analyze_store);
/* or call analyze_load_ipa, analyze_store_ipa */
switch (gimple_code (stmt))
{
@ -705,7 +708,7 @@ analyze_stmt (modref_summary *summary, gimple *stmt, bool ipa,
}
}
/* Analyze function F. IPA indicates whether we're running in tree mode (false)
/* Analyze function F. IPA indicates whether we're running in local mode (false)
or the IPA mode (true). */
static void

2
gcc/ipa-pure-const.c
View File

@ -742,6 +742,8 @@ check_stmt (gimple_stmt_iterator *gsip, funct_state local, bool ipa)
/* Do consider clobber as side effects before IPA, so we rather inline
C++ destructors and keep clobber semantics than eliminate them.
Similar logic is in ipa-modref.
TODO: We may get smarter during early optimizations on these and let
functions containing only clobbers to be optimized more. This is a common
case of C++ destructors. */