[gcc r14-1011] Use get_def_for_expr in fold_single_bit_test

[gcc r14-1011] Use get_def_for_expr in fold_single_bit_test

[Andrew Pinski]

https://gcc.gnu.org/g:3b537ab625ee7dac4f1d601b55b5b623d61d1119

commit r14-1011-g3b537ab625ee7dac4f1d601b55b5b623d61d1119
Author: Andrew Pinski <apinski@marvell.com>
Date:   Fri May 19 18:21:59 2023 +0000

    Use get_def_for_expr in fold_single_bit_test
    
    The code in fold_single_bit_test, checks if
    the inner was a right shift and improve the bitnum
    based on that. But since the inner will always be a
    SSA_NAME at this point, the code is dead. Move it over
    to use the helper function get_def_for_expr instead.
    
    gcc/ChangeLog:
    
            * expr.cc (fold_single_bit_test): Use get_def_for_expr
            instead of checking the inner's code.

Diff:
---
 gcc/expr.cc | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/gcc/expr.cc b/gcc/expr.cc
index 6221b6991c5..a61772b6808 100644
--- a/gcc/expr.cc
+++ b/gcc/expr.cc
@@ -12920,6 +12920,7 @@ fold_single_bit_test (location_t loc, enum tree_code code,
       int ops_unsigned;
       tree signed_type, unsigned_type, intermediate_type;
       tree one;
+      gimple *inner_def;
 
       /* First, see if we can fold the single bit test into a sign-bit
 	 test.  */
@@ -12939,14 +12940,14 @@ fold_single_bit_test (location_t loc, enum tree_code code,
 
       /* If INNER is a right shift of a constant and it plus BITNUM does
 	 not overflow, adjust BITNUM and INNER.  */
-      if (TREE_CODE (inner) == RSHIFT_EXPR
-	  && TREE_CODE (TREE_OPERAND (inner, 1)) == INTEGER_CST
+      if ((inner_def = get_def_for_expr (inner, RSHIFT_EXPR))
+	  && TREE_CODE (gimple_assign_rhs2 (inner_def)) == INTEGER_CST
 	  && bitnum < TYPE_PRECISION (type)
-	  && wi::ltu_p (wi::to_wide (TREE_OPERAND (inner, 1)),
+	  && wi::ltu_p (wi::to_wide (gimple_assign_rhs2 (inner_def)),
 			TYPE_PRECISION (type) - bitnum))
 	{
-	  bitnum += tree_to_uhwi (TREE_OPERAND (inner, 1));
-	  inner = TREE_OPERAND (inner, 0);
+	  bitnum += tree_to_uhwi (gimple_assign_rhs2 (inner_def));
+	  inner = gimple_assign_rhs1 (inner_def);
 	}
 
       /* If we are going to be able to omit the AND below, we must do our