[gcc r12-2558] Don't skip prologue/epilogue when initializing alias.

[gcc r12-2558] Don't skip prologue/epilogue when initializing alias.

[Bin Cheng]

https://gcc.gnu.org/g:0f95c6b2f7dae35ec8c9f211d63edc42baa1d2b7

commit r12-2558-g0f95c6b2f7dae35ec8c9f211d63edc42baa1d2b7
Author: Bin Cheng <bin.cheng@linux.alibaba.com>
Date:   Wed Jul 28 17:44:35 2021 +0800

    Don't skip prologue/epilogue when initializing alias.
    
    Register might be modified in prologue/epilogue, which shouldn't
    be skipped in alias info analysis.
    
    2021-07-28  Bin Cheng  <bin.cheng@linux.alibaba.com>
    
    gcc/
            * alias.c (init_alias_analysis): Don't skip prologue/epilogue.

Diff:
---
 gcc/alias.c | 12 ------------
 1 file changed, 12 deletions(-)

diff --git a/gcc/alias.c b/gcc/alias.c
index 69e1eb89ac6..099acabca6b 100644
--- a/gcc/alias.c
+++ b/gcc/alias.c
@@ -3406,14 +3406,6 @@ init_alias_analysis (void)
   rpo = XNEWVEC (int, n_basic_blocks_for_fn (cfun));
   rpo_cnt = pre_and_rev_post_order_compute (NULL, rpo, false);
 
-  /* The prologue/epilogue insns are not threaded onto the
-     insn chain until after reload has completed.  Thus,
-     there is no sense wasting time checking if INSN is in
-     the prologue/epilogue until after reload has completed.  */
-  bool could_be_prologue_epilogue = ((targetm.have_prologue ()
-				      || targetm.have_epilogue ())
-				     && reload_completed);
-
   pass = 0;
   do
     {
@@ -3459,10 +3451,6 @@ init_alias_analysis (void)
 		{
 		  rtx note, set;
 
-		  if (could_be_prologue_epilogue
-		      && prologue_epilogue_contains (insn))
-		    continue;
-
 		  /* If this insn has a noalias note, process it,  Otherwise,
 		     scan for sets.  A simple set will have no side effects
 		     which could change the base value of any other register.  */