[gcc r14-1600] Improve do_store_flag for single bit when there is no non-zero bits

[Andrew Pinski <pinskia@gcc.gnu.org>]

https://gcc.gnu.org/g:e60593f3881c72a96a3fa4844d73e8a2cd14f670

commit r14-1600-ge60593f3881c72a96a3fa4844d73e8a2cd14f670
Author: Andrew Pinski <apinski@marvell.com>
Date:   Sun Jun 4 19:21:05 2023 -0700

    Improve do_store_flag for single bit when there is no non-zero bits
    
    In r14-1534-g908e5ab5c11c, I forgot you could turn off CCP or
    turn off the bit tracking part of CCP so we would lose out
    what TER was able to do before hand. This moves around the
    TER code so that it is used instead of just the nonzerobits.
    It also makes it easier to remove the TER part of the code
    later on too.
    
    OK? Bootstrapped and tested on x86_64-linux-gnu.
    
    Note it reintroduces PR 110117 (which was accidently fixed after
    r14-1534-g908e5ab5c11c). The next patch in series will fix that.
    
    gcc/ChangeLog:
    
            * expr.cc (do_store_flag): Rearrange the
            TER code so that it overrides the nonzero bits
            info if we had `a & POW2`.

Diff:
---
 gcc/expr.cc | 28 +++++++++++-----------------
 1 file changed, 11 insertions(+), 17 deletions(-)

diff --git a/gcc/expr.cc b/gcc/expr.cc
index 4efb9912c9f..1c5874b0dd0 100644
--- a/gcc/expr.cc
+++ b/gcc/expr.cc
@@ -13158,38 +13158,32 @@ do_store_flag (sepops ops, rtx target, machine_mode mode)
       && (TYPE_PRECISION (ops->type) != 1 || TYPE_UNSIGNED (ops->type)))
     {
       wide_int nz = tree_nonzero_bits (arg0);
+      gimple *srcstmt = get_def_for_expr (arg0, BIT_AND_EXPR);
+      /* If the defining statement was (x & POW2), then use that instead of
+	 the non-zero bits.  */
+      if (srcstmt && integer_pow2p (gimple_assign_rhs2 (srcstmt)))
+	{
+	  nz = wi::to_wide (gimple_assign_rhs2 (srcstmt));
+	  arg0 = gimple_assign_rhs1 (srcstmt);
+	}
 
       if (wi::popcount (nz) == 1
 	  && (integer_zerop (arg1)
 	      || wi::to_wide (arg1) == nz))
 	{
-	  tree op0;
-	  int bitnum;
-	  gimple *srcstmt = get_def_for_expr (arg0, BIT_AND_EXPR);
-	  /* If the defining statement was (x & POW2), then remove the and
-	     as we are going to add it back. */
-	  if (srcstmt
-	      && integer_pow2p (gimple_assign_rhs2 (srcstmt)))
-	    {
-	      op0 = gimple_assign_rhs1 (srcstmt);
-	      bitnum = tree_log2 (gimple_assign_rhs2 (srcstmt));
-	    }
-	  else
-	    {
-	      op0 = arg0;
-	      bitnum = wi::exact_log2 (nz);
-	    }
+	  int bitnum = wi::exact_log2 (nz);
 	  enum tree_code tcode = EQ_EXPR;
 	  if ((code == NE) ^ !integer_zerop (arg1))
 	    tcode = NE_EXPR;
 
 	  type = lang_hooks.types.type_for_mode (mode, unsignedp);
 	  return expand_single_bit_test (loc, tcode,
-					 op0,
+					 arg0,
 					 bitnum, type, target, mode);
 	}
     }
 
+
   if (! get_subtarget (target)
       || GET_MODE (subtarget) != operand_mode)
     subtarget = 0;