[committed] [PR99422] LRA: Skip modifiers when processing memory address.

[Vladimir Makarov via Gcc-patches]

The following patch solves

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99422
The patch was successfully bootstrapped and tested on ppc64le, x86-64 
and arm64.

commit 04b4828c6dd215385fde6964a5e13da8a01a78ba (HEAD -> master)
Author: Vladimir N. Makarov <vmaka...@redhat.com>
Date:   Mon Mar 8 09:24:57 2021 -0500

    [PR99422] LRA: Skip modifiers when processing memory address.
    
      Function process_address_1 can wrongly look at constraint modifiers
    instead of the 1st constraint itself.  The patch solves the problem.
    
    gcc/ChangeLog:
    
            PR target/99422
            * lra-constraints.c (skip_contraint_modifiers): New function.
            (process_address_1): Use it before lookup_constraint call.

diff --git a/gcc/lra-constraints.c b/gcc/lra-constraints.c
index 9253690561a..76e3ff7efe6 100644
--- a/gcc/lra-constraints.c
+++ b/gcc/lra-constraints.c
@@ -3392,6 +3392,21 @@ equiv_address_substitution (struct address_info *ad)
   return change_p;
 }
 
+/* Skip all modifiers and whitespaces in constraint STR and return the
+   result.  */
+static const char *
+skip_contraint_modifiers (const char *str)
+{
+  for (;;str++)
+    switch (*str)
+      {
+      case '+' : case '&' : case '=': case '*': case ' ': case '\t':
+      case '$': case '^' : case '%': case '?': case '!':
+	break;
+      default: return str;
+      }
+}
+
 /* Major function to make reloads for an address in operand NOP or
    check its correctness (If CHECK_ONLY_P is true). The supported
    cases are:
@@ -3426,8 +3441,8 @@ process_address_1 (int nop, bool check_only_p,
   HOST_WIDE_INT scale;
   rtx op = *curr_id->operand_loc[nop];
   rtx mem = extract_mem_from_operand (op);
-  const char *constraint = curr_static_id->operand[nop].constraint;
-  enum constraint_num cn = lookup_constraint (constraint);
+  const char *constraint;
+  enum constraint_num cn;
   bool change_p = false;
 
   if (MEM_P (mem)
@@ -3435,6 +3450,9 @@ process_address_1 (int nop, bool check_only_p,
       && GET_CODE (XEXP (mem, 0)) == SCRATCH)
     return false;
 
+  constraint
+    = skip_contraint_modifiers (curr_static_id->operand[nop].constraint);
+  cn = lookup_constraint (constraint);
   if (insn_extra_address_constraint (cn)
       /* When we find an asm operand with an address constraint that
 	 doesn't satisfy address_operand to begin with, we clear