Fix PR 111331: wrong code for `a > 28 ? MIN<a, 28> : 29`

The problem here is after r6-7425-ga9fee7cdc3c62d0e51730,
the comparison to see if the transformation could be done was using the
wrong value. Instead of see if the inner was LE (for MIN and GE for MAX)
the outer value, it was comparing the inner to the value used in the comparison
which was wrong.

Committed to GCC 13 branch after bootstrapped and tested on x86_64-linux-gnu.

gcc/ChangeLog:

	PR tree-optimization/111331
	* tree-ssa-phiopt.c (minmax_replacement):
	Fix the LE/GE comparison for the
	`(a CMP CST1) ? max<a,CST2> : a` optimization.

gcc/testsuite/ChangeLog:

	PR tree-optimization/111331
	* gcc.c-torture/execute/pr111331-1.c: New test.
	* gcc.c-torture/execute/pr111331-2.c: New test.
	* gcc.c-torture/execute/pr111331-3.c: New test.

(cherry picked from commit 30e6ee074588bacefd2dfe745b188bb20c81fe5e)

diff --git a/gcc/testsuite/gcc.c-torture/execute/pr111331-1.c b/gcc/testsuite/gcc.c-torture/execute/pr111331-1.c
new file mode 100644 (file)
index 0000000..4c7f4fd
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/pr111331-1.c
@@ -0,0 +1,17 @@
+int a;
+int b;
+int c(int d, int e, int f) {
+  if (d < e)
+    return e;
+  if (d > f)
+    return f;
+  return d;
+}
+int main() {
+  int g = -1;
+  a = c(b + 30, 29, g + 29);
+  volatile t = a;
+  if (t != 28)
+    __builtin_abort();
+  return 0;
+}

diff --git a/gcc/testsuite/gcc.c-torture/execute/pr111331-2.c b/gcc/testsuite/gcc.c-torture/execute/pr111331-2.c
new file mode 100644 (file)
index 0000000..5c677f2
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/pr111331-2.c
@@ -0,0 +1,19 @@
+
+int a;
+int b;
+
+int main() {
+  int d = b+30;
+  {
+        int t;
+        if (d < 29)
+          t =  29;
+        else
+          t = (d > 28) ? 28 : d;
+    a = t;
+  }
+  volatile int t = a;
+  if (a != 28)
+    __builtin_abort();
+  return 0;
+}

diff --git a/gcc/testsuite/gcc.c-torture/execute/pr111331-3.c b/gcc/testsuite/gcc.c-torture/execute/pr111331-3.c
new file mode 100644 (file)
index 0000000..213d9bd
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/pr111331-3.c
@@ -0,0 +1,15 @@
+int a;
+int b;
+
+int main() {
+  int d = b+30;
+  {
+    int t;
+    t = d < 29 ? 29 : ((d > 28) ? 28 : d);
+    a = t;
+  }
+  volatile int t = a;
+  if (a != 28)
+    __builtin_abort();
+  return 0;
+}

diff --git a/gcc/tree-ssa-phiopt.c b/gcc/tree-ssa-phiopt.c
index 5831a7764a49e694f09f7c71ae7cf0f0c6750669..d26d7889d9521e39332a3a06e3c7b64525b3bde6 100644 (file)
--- a/gcc/tree-ssa-phiopt.c
+++ b/gcc/tree-ssa-phiopt.c
@@ -1676,7 +1676,7 @@ minmax_replacement (basic_block cond_bb, basic_block middle_bb,
 
              /* We need BOUND <= LARGER.  */
              if (!integer_nonzerop (fold_build2 (LE_EXPR, boolean_type_node,
-                                                 bound, larger)))
+                                                 bound, arg_false)))
                return false;
            }
          else if (operand_equal_for_phi_arg_p (arg_false, smaller)
@@ -1707,7 +1707,7 @@ minmax_replacement (basic_block cond_bb, basic_block middle_bb,
 
              /* We need BOUND >= SMALLER.  */
              if (!integer_nonzerop (fold_build2 (GE_EXPR, boolean_type_node,
-                                                 bound, smaller)))
+                                                 bound, arg_false)))
                return false;
            }
          else
@@ -1747,7 +1747,7 @@ minmax_replacement (basic_block cond_bb, basic_block middle_bb,
 
              /* We need BOUND >= LARGER.  */
              if (!integer_nonzerop (fold_build2 (GE_EXPR, boolean_type_node,
-                                                 bound, larger)))
+                                                 bound, arg_true)))
                return false;
            }
          else if (operand_equal_for_phi_arg_p (arg_true, smaller)
@@ -1774,7 +1774,7 @@ minmax_replacement (basic_block cond_bb, basic_block middle_bb,
 
              /* We need BOUND <= SMALLER.  */
              if (!integer_nonzerop (fold_build2 (LE_EXPR, boolean_type_node,
-                                                 bound, smaller)))
+                                                 bound, arg_true)))
                return false;
            }
          else