Richard Sandiford <richard.sandif...@arm.com> writes:
> 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.
Similary to the combine patch, I've updated this to avoid the
short "abi" name and use a temporary HARD_REG_SET instead.
Richard
2019-09-25 Richard Sandiford <richard.sandif...@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.
Index: gcc/cse.c
===================================================================
--- gcc/cse.c 2019-09-17 15:27:11.338066929 +0100
+++ gcc/cse.c 2019-09-25 16:55:31.202641509 +0100
@@ -42,6 +42,8 @@ Software Foundation; either version 3, o
#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 (
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 +2092,29 @@ 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. */
+ 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 +2139,11 @@ 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 +5826,7 @@ 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.
