xtensa: Fix the regression introduce by r15-959-gbe9b3f4375e7

It is not wrong but also not optimal to specify that sibcalls require
register A0 in RTX generation pass, by misleading DFA into thinking it
is being used in function body.
It would be better to specify it in pro_and_epilogue as with 'return'
insn in order to avoid incorrect removing load that restores A0 in
subsequent passes, but since it is not possible to modify each sibcall
there, as a workaround we will preface it with a 'use' as before.

This patch effectively reverts commit r15-959-gbe9b3f4375e7

gcc/ChangeLog:

	* config/xtensa/xtensa-protos.h (xtensa_expand_call):
	Remove the third argument.
	* config/xtensa/xtensa.cc (xtensa_expand_call):
	Remove the third argument and the code that uses it.
	* config/xtensa/xtensa.md (call, call_value, sibcall, sibcall_value):
	Remove each Boolean constant specified in the third argument of
	xtensa_expand_call.
	(sibcall_epilogue): Add emitting '(use A0_REG)' after calling
	xtensa_expand_epilogue.

diff --git a/gcc/config/xtensa/xtensa-protos.h b/gcc/config/xtensa/xtensa-protos.h
index 8f645e87de96842660f21b1a78615a102850afd1..3646ceaa09385f7f458f05e0bddc01a2777ca248 100644 (file)
--- a/gcc/config/xtensa/xtensa-protos.h
+++ b/gcc/config/xtensa/xtensa-protos.h
@@ -53,7 +53,7 @@ extern void xtensa_expand_atomic (enum rtx_code, rtx, rtx, rtx, bool);
 extern void xtensa_emit_loop_end (rtx_insn *, rtx *);
 extern char *xtensa_emit_branch (bool, rtx *);
 extern char *xtensa_emit_movcc (bool, bool, bool, rtx *);
-extern void xtensa_expand_call (int, rtx *, bool);
+extern void xtensa_expand_call (int, rtx *);
 extern char *xtensa_emit_call (int, rtx *);
 extern char *xtensa_emit_sibcall (int, rtx *);
 extern bool xtensa_tls_referenced_p (rtx);

diff --git a/gcc/config/xtensa/xtensa.cc b/gcc/config/xtensa/xtensa.cc
index 772150c7fa228ca2f80af94df0bb322492db0496..1ccd42bcda890990937cc31920043aa30d40bdd8 100644 (file)
--- a/gcc/config/xtensa/xtensa.cc
+++ b/gcc/config/xtensa/xtensa.cc
@@ -2297,7 +2297,7 @@ xtensa_emit_movcc (bool inverted, bool isfp, bool isbool, rtx *operands)
 
 
 void
-xtensa_expand_call (int callop, rtx *operands, bool sibcall_p)
+xtensa_expand_call (int callop, rtx *operands)
 {
   rtx call;
   rtx_insn *call_insn;
@@ -2339,14 +2339,6 @@ xtensa_expand_call (int callop, rtx *operands, bool sibcall_p)
       CALL_INSN_FUNCTION_USAGE (call_insn) =
        gen_rtx_EXPR_LIST (Pmode, clob, CALL_INSN_FUNCTION_USAGE (call_insn));
     }
-  else if (sibcall_p)
-    {
-      /* Sibling call requires a return address to the caller, similar to
-        "return" insn.  */
-      rtx use = gen_rtx_USE (VOIDmode, gen_rtx_REG (SImode, A0_REG));
-      CALL_INSN_FUNCTION_USAGE (call_insn) =
-       gen_rtx_EXPR_LIST (Pmode, use, CALL_INSN_FUNCTION_USAGE (call_insn));
-    }
 }
 
 

diff --git a/gcc/config/xtensa/xtensa.md b/gcc/config/xtensa/xtensa.md
index 376d0f75544632bb2930f405464bfafe59f168aa..a3b99dc381de92d0332701f7c5887e1fc01698d9 100644 (file)
--- a/gcc/config/xtensa/xtensa.md
+++ b/gcc/config/xtensa/xtensa.md
@@ -2597,7 +2597,7 @@
         (match_operand 1 "" ""))]
   ""
 {
-  xtensa_expand_call (0, operands, false);
+  xtensa_expand_call (0, operands);
   DONE;
 })
 
@@ -2618,7 +2618,7 @@
              (match_operand 2 "" "")))]
   ""
 {
-  xtensa_expand_call (1, operands, false);
+  xtensa_expand_call (1, operands);
   DONE;
 })
 
@@ -2639,7 +2639,7 @@
         (match_operand 1 "" ""))]
   "!TARGET_WINDOWED_ABI"
 {
-  xtensa_expand_call (0, operands, true);
+  xtensa_expand_call (0, operands);
   DONE;
 })
 
@@ -2660,7 +2660,7 @@
              (match_operand 2 "" "")))]
   "!TARGET_WINDOWED_ABI"
 {
-  xtensa_expand_call (1, operands, true);
+  xtensa_expand_call (1, operands);
   DONE;
 })
 
@@ -2777,6 +2777,7 @@
   "!TARGET_WINDOWED_ABI"
 {
   xtensa_expand_epilogue ();
+  emit_use (gen_rtx_REG (SImode, A0_REG));
   DONE;
 })