[gcc r14-4303] tree-optimization/111614 - missing convert in undistribute_bitref_for_vector

[gcc r14-4303] tree-optimization/111614 - missing convert in undistribute_bitref_for_vector

[Richard Biener]

https://gcc.gnu.org/g:88d79b9b03eccf39921d13c2cbd1acc50aeda126

commit r14-4303-g88d79b9b03eccf39921d13c2cbd1acc50aeda126
Author: Richard Biener <rguenther@suse.de>
Date:   Thu Sep 28 09:41:30 2023 +0200

    tree-optimization/111614 - missing convert in undistribute_bitref_for_vector
    
    The following adjusts a flawed guard for converting the first vector
    of the sum we create in undistribute_bitref_for_vector.
    
            PR tree-optimization/111614
            * tree-ssa-reassoc.cc (undistribute_bitref_for_vector): Properly
            convert the first vector when required.
    
            * gcc.dg/torture/pr111614.c: New testcase.

Diff:
---
 gcc/testsuite/gcc.dg/torture/pr111614.c | 23 +++++++++++++++++++++++
 gcc/tree-ssa-reassoc.cc                 | 27 +++++++++++++++------------
 2 files changed, 38 insertions(+), 12 deletions(-)

diff --git a/gcc/testsuite/gcc.dg/torture/pr111614.c b/gcc/testsuite/gcc.dg/torture/pr111614.c
new file mode 100644
index 00000000000..0f3ecbae86c
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr111614.c
@@ -0,0 +1,23 @@
+/* { dg-do compile } */
+
+int a, b, c, d, e;
+static void f() {
+  int *g = &b;
+  b = 1;
+  for (; b >= 0; b--) {
+    c = 0;
+    for (; c <= 1; c++)
+      e = 0;
+    for (; e <= 1; e++) {
+      int h, i = h = 13;
+      for (; h; h--)
+        i = i << a;
+      d &= i + c + 9 + *g;
+    }
+  }
+}
+int main() {
+  f();
+  for (;;)
+    ;
+}
diff --git a/gcc/tree-ssa-reassoc.cc b/gcc/tree-ssa-reassoc.cc
index eda03bf98a6..41ee36413b5 100644
--- a/gcc/tree-ssa-reassoc.cc
+++ b/gcc/tree-ssa-reassoc.cc
@@ -2102,12 +2102,24 @@ undistribute_bitref_for_vector (enum tree_code opcode,
 	{
 	  sum = build_and_add_sum (vec_type, sum_vec,
 				   valid_vecs[i + 1], opcode);
+	  /* Update the operands only after build_and_add_sum,
+	     so that we don't have to repeat the placement algorithm
+	     of build_and_add_sum.  */
+	  if (sum_vec == tvec
+	      && !useless_type_conversion_p (vec_type, TREE_TYPE (sum_vec)))
+	    {
+	      gimple_stmt_iterator gsi = gsi_for_stmt (sum);
+	      tree vce = build1 (VIEW_CONVERT_EXPR, vec_type, sum_vec);
+	      tree lhs = make_ssa_name (vec_type);
+	      gimple *g = gimple_build_assign (lhs, VIEW_CONVERT_EXPR, vce);
+	      gimple_set_uid (g, gimple_uid (sum));
+	      gsi_insert_before (&gsi, g, GSI_NEW_STMT);
+	      gimple_assign_set_rhs1 (sum, lhs);
+	      update_stmt (sum);
+	    }
 	  if (!useless_type_conversion_p (vec_type,
 					  TREE_TYPE (valid_vecs[i + 1])))
 	    {
-	      /* Update the operands only after build_and_add_sum,
-		 so that we don't have to repeat the placement algorithm
-		 of build_and_add_sum.  */
 	      gimple_stmt_iterator gsi = gsi_for_stmt (sum);
 	      tree vce = build1 (VIEW_CONVERT_EXPR, vec_type,
 				 valid_vecs[i + 1]);
@@ -2116,15 +2128,6 @@ undistribute_bitref_for_vector (enum tree_code opcode,
 	      gimple_set_uid (g, gimple_uid (sum));
 	      gsi_insert_before (&gsi, g, GSI_NEW_STMT);
 	      gimple_assign_set_rhs2 (sum, lhs);
-	      if (sum_vec == tvec)
-		{
-		  vce = build1 (VIEW_CONVERT_EXPR, vec_type, sum_vec);
-		  lhs = make_ssa_name (vec_type);
-		  g = gimple_build_assign (lhs, VIEW_CONVERT_EXPR, vce);
-		  gimple_set_uid (g, gimple_uid (sum));
-		  gsi_insert_before (&gsi, g, GSI_NEW_STMT);
-		  gimple_assign_set_rhs1 (sum, lhs);
-		}
 	      update_stmt (sum);
 	    }
 	  sum_vec = gimple_get_lhs (sum);