From: Jakub Jelinek <jakub@redhat.com>
Date: Thu, 19 Jan 2023 20:22:22 +0000 (+0100)
Subject: openmp: Fix up OpenMP expansion of non-rectangular loops [PR108459]
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1184c551867f870ce880578153b5d961c4723efb;p=thirdparty%2Fgcc.git

openmp: Fix up OpenMP expansion of non-rectangular loops [PR108459]

expand_omp_for_init_counts was using for the case where collapse(2)
inner loop has init expression dependent on non-constant multiple of
the outer iterator and the condition upper bound expression doesn't
depend on the outer iterator fold_unary (NEGATE_EXPR, ...).  This
will just return NULL if it can't be folded, we need fold_build1
instead.

2023-01-19  Jakub Jelinek  <jakub@redhat.com>

	PR middle-end/108459
	* omp-expand.cc (expand_omp_for_init_counts): Use fold_build1 rather
	than fold_unary for NEGATE_EXPR.

	* testsuite/libgomp.c/pr108459.c: New test.

(cherry picked from commit 46644ec99cb355845b23bb1d02775c057ed8ee88)
---

diff --git a/gcc/ChangeLog.omp b/gcc/ChangeLog.omp
index 917bb606a0f9..2d4b75134138 100644
--- a/gcc/ChangeLog.omp
+++ b/gcc/ChangeLog.omp
@@ -1,3 +1,12 @@
+2023-01-19  Tobias Burnus  <tobias@codesourcery.com>
+
+	Backported from master:
+	2023-01-19  Jakub Jelinek  <jakub@redhat.com>
+
+	PR middle-end/108459
+	* omp-expand.cc (expand_omp_for_init_counts): Use fold_build1 rather
+	than fold_unary for NEGATE_EXPR.
+
 2023-01-03  Sandra Loosemore  <sandra@codesourcery.com>
 
 	Backported from master:
diff --git a/gcc/omp-expand.cc b/gcc/omp-expand.cc
index 37c397089b48..afe00069a56d 100644
--- a/gcc/omp-expand.cc
+++ b/gcc/omp-expand.cc
@@ -2009,8 +2009,8 @@ expand_omp_for_init_counts (struct omp_for_data *fd, gimple_stmt_iterator *gsi,
 	    t = fold_build2 (MINUS_EXPR, itype, unshare_expr (fd->loops[i].m2),
 			     unshare_expr (fd->loops[i].m1));
 	  else if (fd->loops[i].m1)
-	    t = fold_unary (NEGATE_EXPR, itype,
-			    unshare_expr (fd->loops[i].m1));
+	    t = fold_build1 (NEGATE_EXPR, itype,
+			     unshare_expr (fd->loops[i].m1));
 	  else
 	    t = unshare_expr (fd->loops[i].m2);
 	  tree m2minusm1
diff --git a/libgomp/ChangeLog.omp b/libgomp/ChangeLog.omp
index be3c17b4019c..629efbc58323 100644
--- a/libgomp/ChangeLog.omp
+++ b/libgomp/ChangeLog.omp
@@ -1,3 +1,11 @@
+2023-01-19  Tobias Burnus  <tobias@codesourcery.com>
+
+	Backported from master:
+	2023-01-19  Jakub Jelinek  <jakub@redhat.com>
+
+	PR middle-end/108459
+	* testsuite/libgomp.c/pr108459.c: New test.
+
 2023-01-13  Andrew Stubbs  <ams@codesourcery.com>
 
 	* usm-allocator.c (ALIGN): Use 128-byte alignment.
diff --git a/libgomp/testsuite/libgomp.c/pr108459.c b/libgomp/testsuite/libgomp.c/pr108459.c
new file mode 100644
index 000000000000..87ce981e0807
--- /dev/null
+++ b/libgomp/testsuite/libgomp.c/pr108459.c
@@ -0,0 +1,41 @@
+/* PR middle-end/108459 */
+
+char a[17][17];
+
+__attribute__((noipa)) void
+foo (int x, int y)
+{
+  #pragma omp for collapse(2)
+  for (int i = 1; i <= 16; i++)
+    for (int j = i * x + y; j <= 16; j++)
+      a[i][j] = 1;
+}
+
+int
+main ()
+{
+  #pragma omp parallel
+  foo (1, 1);
+  for (int i = 0; i <= 16; i++)
+    for (int j = 0; j <= 16; j++)
+      if (i >= 1 && j >= i + 1)
+	{
+	  if (a[i][j] != 1)
+	    __builtin_abort ();
+	  a[i][j] = 0;
+	}
+      else if (a[i][j])
+	__builtin_abort ();
+  #pragma omp parallel
+  foo (2, -2);
+  for (int i = 0; i <= 16; i++)
+    for (int j = 0; j <= 16; j++)
+      if (i >= 1 && j >= 2 * i - 2)
+	{
+	  if (a[i][j] != 1)
+	    __builtin_abort ();
+	}
+      else if (a[i][j])
+	__builtin_abort ();
+  return 0;
+}