diff mbox

[00/32] Remove global call sets: rtlanal.c

Message ID mpt4l1ive15.fsf@arm.com
State New
Headers show

Commit Message

Richard Sandiford Sept. 11, 2019, 7:17 p.m. UTC 
The reg_set_p part is simple, since the caller is asking about
a specific REG rtx, with a known register number and mode.

The find_all_hard_reg_sets part emphasises that the "implicit"
behaviour was always a bit suspect, since it includes fully-clobbered
registers but not partially-clobbered registers.  The only current
user of this path is the c6x-specific scheduler predication code,
and c6x doesn't have partly call-clobbered registers, so in practice
it's fine.  I've added a comment to try to disuade future users.
(The !implicit path is OK and useful though.)


2019-09-11  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	* rtlanal.c: Include function-abi.h.
	(reg_set_p): Use call_insn_abi to get the ABI of the called
	function and clobbers_reg_p to test whether the register
	is call-clobbered.
	(find_all_hard_reg_sets): When implicit is true, use call_insn_abi
	to get the ABI of the called function and full_reg_clobbers to
	get the set of fully call-clobbered registers.  Warn about the
	pitfalls of using this mode.

Comments

Jeff Law Sept. 29, 2019, 10:21 p.m. UTC | #1 
On 9/11/19 1:17 PM, Richard Sandiford wrote:
> The reg_set_p part is simple, since the caller is asking about
> a specific REG rtx, with a known register number and mode.
> 
> The find_all_hard_reg_sets part emphasises that the "implicit"
> behaviour was always a bit suspect, since it includes fully-clobbered
> registers but not partially-clobbered registers.  The only current
> user of this path is the c6x-specific scheduler predication code,
> and c6x doesn't have partly call-clobbered registers, so in practice
> it's fine.  I've added a comment to try to disuade future users.
> (The !implicit path is OK and useful though.)
> 
> 
> 2019-09-11  Richard Sandiford  <richard.sandiford@arm.com>
> 
> gcc/
> 	* rtlanal.c: Include function-abi.h.
> 	(reg_set_p): Use call_insn_abi to get the ABI of the called
> 	function and clobbers_reg_p to test whether the register
> 	is call-clobbered.
> 	(find_all_hard_reg_sets): When implicit is true, use call_insn_abi
> 	to get the ABI of the called function and full_reg_clobbers to
> 	get the set of fully call-clobbered registers.  Warn about the
> 	pitfalls of using this mode.
OK
jeff
diff mbox

Patch

Index: gcc/rtlanal.c
===================================================================
--- gcc/rtlanal.c	2019-09-11 19:47:24.418262673 +0100
+++ gcc/rtlanal.c	2019-09-11 19:49:04.417558020 +0100
@@ -36,6 +36,7 @@  Software Foundation; either version 3, o
 #include "addresses.h"
 #include "rtl-iter.h"
 #include "hard-reg-set.h"
+#include "function-abi.h"
 
 /* Forward declarations */
 static void set_of_1 (rtx, const_rtx, void *);
@@ -1270,8 +1271,8 @@  reg_set_p (const_rtx reg, const_rtx insn
 	  || (CALL_P (insn)
 	      && ((REG_P (reg)
 		   && REGNO (reg) < FIRST_PSEUDO_REGISTER
-		   && overlaps_hard_reg_set_p (regs_invalidated_by_call,
-					       GET_MODE (reg), REGNO (reg)))
+		   && (call_insn_abi (as_a<const rtx_insn *> (insn))
+		       .clobbers_reg_p (GET_MODE (reg), REGNO (reg))))
 		  || MEM_P (reg)
 		  || find_reg_fusage (insn, CLOBBER, reg)))))
     return true;
@@ -1486,7 +1487,11 @@  record_hard_reg_sets (rtx x, const_rtx p
 }
 
 /* Examine INSN, and compute the set of hard registers written by it.
-   Store it in *PSET.  Should only be called after reload.  */
+   Store it in *PSET.  Should only be called after reload.
+
+   IMPLICIT is true if we should include registers that are fully-clobbered
+   by calls.  This should be used with caution, since it doesn't include
+   partially-clobbered registers.  */
 void
 find_all_hard_reg_sets (const rtx_insn *insn, HARD_REG_SET *pset, bool implicit)
 {
@@ -1495,7 +1500,7 @@  find_all_hard_reg_sets (const rtx_insn *
   CLEAR_HARD_REG_SET (*pset);
   note_stores (insn, record_hard_reg_sets, pset);
   if (CALL_P (insn) && implicit)
-    *pset |= call_used_or_fixed_regs;
+    *pset |= call_insn_abi (insn).full_reg_clobbers ();
   for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
     if (REG_NOTE_KIND (link) == REG_INC)
       record_hard_reg_sets (XEXP (link, 0), NULL, pset);