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Remove global call sets: cse.c 

Like with the combine.c patch, this one keeps things simple by
invalidating values in partially-clobbered registers, rather than
trying to tell whether the value in a partially-clobbered register
is actually clobbered or not.  Again, this is in principle a bug fix,
but probably never matters in practice.

2019-09-30  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	* cse.c: Include regs.h and function-abi.h.
	(invalidate_for_call): Take the call insn as an argument.
	Use insn_callee_abi to get the ABI of the call and invalidate
	partially clobbered registers as well as fully clobbered ones.
	(cse_insn): Update call accordingly.

From-SVN: r276317
This commit is contained in:
Richard Sandiford 2019-09-30 16:20:23 +00:00 committed by Richard Sandiford
parent 212b7076ee
commit 311b62ce03
2 changed files with 32 additions and 19 deletions
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8
gcc/ChangeLog
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@ -1,3 +1,11 @@
2019-09-30 Richard Sandiford <richard.sandiford@arm.com>
* cse.c: Include regs.h and function-abi.h.
(invalidate_for_call): Take the call insn as an argument.
Use insn_callee_abi to get the ABI of the call and invalidate
partially clobbered registers as well as fully clobbered ones.
(cse_insn): Update call accordingly.
2019-09-30 Richard Sandiford <richard.sandiford@arm.com>
* combine.c: Include function-abi.h.

43
gcc/cse.c
View File

@ -42,6 +42,8 @@ along with GCC; see the file COPYING3. If not see
#include "tree-pass.h"
#include "dbgcnt.h"
#include "rtl-iter.h"
#include "regs.h"
#include "function-abi.h"
/* The basic idea of common subexpression elimination is to go
through the code, keeping a record of expressions that would
@ -566,7 +568,6 @@ static void remove_invalid_subreg_refs (unsigned int, poly_uint64,
machine_mode);
static void rehash_using_reg (rtx);
static void invalidate_memory (void);
static void invalidate_for_call (void);
static rtx use_related_value (rtx, struct table_elt *);
static inline unsigned canon_hash (rtx, machine_mode);
@ -2091,23 +2092,31 @@ rehash_using_reg (rtx x)
}
/* Remove from the hash table any expression that is a call-clobbered
register. Also update their TICK values. */
register in INSN. Also update their TICK values. */
static void
invalidate_for_call (void)
invalidate_for_call (rtx_insn *insn)
{
unsigned int regno, endregno;
unsigned int i;
unsigned int regno;
unsigned hash;
struct table_elt *p, *next;
int in_table = 0;
hard_reg_set_iterator hrsi;
/* Go through all the hard registers. For each that is clobbered in
a CALL_INSN, remove the register from quantity chains and update
/* Go through all the hard registers. For each that might be clobbered
in call insn INSN, remove the register from quantity chains and update
reg_tick if defined. Also see if any of these registers is currently
in the table. */
EXECUTE_IF_SET_IN_HARD_REG_SET (regs_invalidated_by_call, 0, regno, hrsi)
in the table.
??? We could be more precise for partially-clobbered registers,
and only invalidate values that actually occupy the clobbered part
of the registers. It doesn't seem worth the effort though, since
we shouldn't see this situation much before RA. Whatever choice
we make here has to be consistent with the table walk below,
so any change to this test will require a change there too. */
HARD_REG_SET callee_clobbers
= insn_callee_abi (insn).full_and_partial_reg_clobbers ();
EXECUTE_IF_SET_IN_HARD_REG_SET (callee_clobbers, 0, regno, hrsi)
{
delete_reg_equiv (regno);
if (REG_TICK (regno) >= 0)
@ -2132,15 +2141,11 @@ invalidate_for_call (void)
|| REGNO (p->exp) >= FIRST_PSEUDO_REGISTER)
continue;
regno = REGNO (p->exp);
endregno = END_REGNO (p->exp);
for (i = regno; i < endregno; i++)
if (TEST_HARD_REG_BIT (regs_invalidated_by_call, i))
{
remove_from_table (p, hash);
break;
}
/* This must use the same test as above rather than the
more accurate clobbers_reg_p. */
if (overlaps_hard_reg_set_p (callee_clobbers, GET_MODE (p->exp),
REGNO (p->exp)))
remove_from_table (p, hash);
}
}
@ -5823,7 +5828,7 @@ cse_insn (rtx_insn *insn)
if (GET_CODE (XEXP (tem, 0)) == USE
&& MEM_P (XEXP (XEXP (tem, 0), 0)))
invalidate (XEXP (XEXP (tem, 0), 0), VOIDmode);
invalidate_for_call ();
invalidate_for_call (insn);
}
/* Now invalidate everything set by this instruction.