From: Andrew Pinski <apinski@marvell.com>
Date: Fri, 8 Sep 2023 05:13:31 +0000 (-0700)
Subject: Fix PR 111331: wrong code for `a > 28 ? MIN<a, 28> : 29`
X-Git-Tag: basepoints/gcc-15~6312
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=30e6ee074588bacefd2dfe745b188bb20c81fe5e;p=thirdparty%2Fgcc.git

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.
The match pattern copied the same logic mistake when they were added in
r14-1411-g17cca3c43e2f49 .

OK? Bootstrapped and tested on x86_64-linux-gnu.

gcc/ChangeLog:

	PR tree-optimization/111331
	* match.pd (`(a CMP CST1) ? max<a,CST2> : a`):
	Fix the LE/GE comparison to the correct value.
	* tree-ssa-phiopt.cc (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.
---

diff --git a/gcc/match.pd b/gcc/match.pd
index 8c24dae71cd4..c7b6db4b5436 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -5438,11 +5438,11 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
     }
     (if ((cmp == LT_EXPR || cmp == LE_EXPR)
 	 && code == MIN_EXPR
-         && integer_nonzerop (fold_build2 (LE_EXPR, boolean_type_node, @3, @1)))
+         && integer_nonzerop (fold_build2 (LE_EXPR, boolean_type_node, @3, @4)))
      (min @2 @4)
      (if ((cmp == GT_EXPR || cmp == GE_EXPR)
 	  && code == MAX_EXPR
-          && integer_nonzerop (fold_build2 (GE_EXPR, boolean_type_node, @3, @1)))
+          && integer_nonzerop (fold_build2 (GE_EXPR, boolean_type_node, @3, @4)))
       (max @2 @4))))))
 
 #if GIMPLE
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
index 000000000000..4c7f4fdbaa9d
--- /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
index 000000000000..5c677f2caa9f
--- /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
index 000000000000..213d9bdd539d
--- /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.cc b/gcc/tree-ssa-phiopt.cc
index 3148ad38e234..3835d25d08c4 100644
--- a/gcc/tree-ssa-phiopt.cc
+++ b/gcc/tree-ssa-phiopt.cc
@@ -2070,7 +2070,7 @@ minmax_replacement (basic_block cond_bb, basic_block middle_bb, basic_block alt_
 
 	      /* 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)
@@ -2101,7 +2101,7 @@ minmax_replacement (basic_block cond_bb, basic_block middle_bb, basic_block alt_
 
 	      /* We need BOUND >= SMALLER.  */
 	      if (!integer_nonzerop (fold_build2 (GE_EXPR, boolean_type_node,
-						  bound, smaller)))
+						  bound, arg_false)))
 		return false;
 	    }
 	  else
@@ -2141,7 +2141,7 @@ minmax_replacement (basic_block cond_bb, basic_block middle_bb, basic_block alt_
 
 	      /* 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)
@@ -2168,7 +2168,7 @@ minmax_replacement (basic_block cond_bb, basic_block middle_bb, basic_block alt_
 
 	      /* We need BOUND <= SMALLER.  */
 	      if (!integer_nonzerop (fold_build2 (LE_EXPR, boolean_type_node,
-						  bound, smaller)))
+						  bound, arg_true)))
 		return false;
 	    }
 	  else