From: Jakub Jelinek <jakub@redhat.com>
Date: Sat, 11 Nov 2023 19:15:53 +0000 (+0100)
Subject: tree-ssa-math-opts: Fix up gsi_remove order in match_uaddc_usubc [PR112430]
X-Git-Tag: basepoints/gcc-15~4773
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=7610e5cc82bd6316cfe0bfee6d9f12d8c2cfa9c3;p=thirdparty%2Fgcc.git

tree-ssa-math-opts: Fix up gsi_remove order in match_uaddc_usubc [PR112430]

The following testcase ICEs, because the temp_stmts were removed in
wrong order, from the ones appearing earlier in the IL to the later ones,
so insert_debug_temps_for_defs can reintroduce dead SSA_NAMEs back into the
IL.

The following patch fixes that by removing them in the order they were
pushed into the vector, which is from later ones to earlier ones.
Additionally, I've noticed I forgot to call release_defs on the removed
stmts.

2023-11-11  Jakub Jelinek  <jakub@redhat.com>

	PR middle-end/112430
	* tree-ssa-math-opts.cc (match_uaddc_usubc): Remove temp_stmts in the
	order they were pushed rather than in reverse order.  Call
	release_defs after gsi_remove.

	* gcc.dg/pr112430.c: New test.
---

diff --git a/gcc/testsuite/gcc.dg/pr112430.c b/gcc/testsuite/gcc.dg/pr112430.c
new file mode 100644
index 000000000000..16c34fcbc69d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr112430.c
@@ -0,0 +1,30 @@
+/* PR middle-end/112430 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -g" } */
+
+int a, b, c, d, e;
+unsigned int f;
+
+static void
+foo (unsigned int x)
+{
+  unsigned int g = x < c;
+  int h = f < b;
+  x += h;
+  g += x < h;
+  f = x;
+  x = g;
+  g = f += a;
+  h = f < a;
+  x += h;
+  c += f < d;
+  x += c;
+  g += x < c;
+  e = g;
+}
+
+void
+bar (unsigned int x)
+{
+  foo (x);
+}
diff --git a/gcc/tree-ssa-math-opts.cc b/gcc/tree-ssa-math-opts.cc
index 363f31646691..95eda438831b 100644
--- a/gcc/tree-ssa-math-opts.cc
+++ b/gcc/tree-ssa-math-opts.cc
@@ -5047,11 +5047,11 @@ match_uaddc_usubc (gimple_stmt_iterator *gsi, gimple *stmt, tree_code code)
       gsi_insert_before (gsi, g, GSI_SAME_STMT);
       /* Remove some further statements which can't be kept in the IL because
 	 they can use SSA_NAMEs whose setter is going to be removed too.  */
-      while (temp_stmts.length ())
+      for (gimple *g2 : temp_stmts)
 	{
-	  g = temp_stmts.pop ();
-	  gsi2 = gsi_for_stmt (g);
+	  gsi2 = gsi_for_stmt (g2);
 	  gsi_remove (&gsi2, true);
+	  release_defs (g2);
 	}
     }
   else
@@ -5068,10 +5068,12 @@ match_uaddc_usubc (gimple_stmt_iterator *gsi, gimple *stmt, tree_code code)
 	rhs1 = gimple_assign_rhs1 (g);
 	gsi2 = gsi_for_stmt (g);
 	gsi_remove (&gsi2, true);
+	release_defs (g);
       }
   gcc_checking_assert (rhs1 == gimple_assign_lhs (im2));
   gsi2 = gsi_for_stmt (im2);
   gsi_remove (&gsi2, true);
+  release_defs (im2);
   /* Replace the re2 statement with __real__ of the newly added
      .UADDC/.USUBC call.  */
   if (re2)