re PR tree-optimization/89430 (A missing ifcvt optimization to generate csel)

2019-07-12  Jiangning Liu  <jiangning.liu@amperecomputing.com>

	PR tree-optimization/89430
	* tree-ssa-phiopt.c (cond_store_replacement): Support conditional
	store elimination for local variable without address escape.

	PR tree-optimization/89430
	* gcc.dg/tree-ssa/pr89430-1.c: New test.
	* gcc.dg/tree-ssa/pr89430-2.c: New test.
	* gcc.dg/tree-ssa/pr89430-3.c: New test.
	* gcc.dg/tree-ssa/pr89430-4.c: New test.
	* gcc.dg/tree-ssa/pr89430-5.c: New test.
	* gcc.dg/tree-ssa/pr89430-6.c: New test.

From-SVN: r273449

gcc/ChangeLog

+2019-07-12  Jiangning Liu  <jiangning.liu@amperecomputing.com>
+
+	PR tree-optimization/89430
+	* tree-ssa-phiopt.c (cond_store_replacement): Support conditional
+	store elimination for local variable without address escape.
+
 2019-07-12  Jeff Law  <law@redhat.com>
 
 	* config/c6x/c6x.c (c6x_section_type): Clear SECTION_NOTYPE

gcc/testsuite/ChangeLog

+2019-07-08  Jiangning Liu  <jiangning.liu@amperecomputing.com>
+
+	PR tree-optimization/89430
+	* gcc.dg/tree-ssa/pr89430-1.c: New test.
+	* gcc.dg/tree-ssa/pr89430-2.c: New test.
+	* gcc.dg/tree-ssa/pr89430-3.c: New test.
+	* gcc.dg/tree-ssa/pr89430-4.c: New test.
+	* gcc.dg/tree-ssa/pr89430-5.c: New test.
+	* gcc.dg/tree-ssa/pr89430-6.c: New test.
+
 2019-07-12  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/91145

gcc/testsuite/gcc.dg/tree-ssa/pr89430-1.c

+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-cselim-details" } */
+
+unsigned test(unsigned k, unsigned b) {
+        unsigned a[2];
+        if (b < a[k]) {
+                a[k] = b;
+        }
+        return a[0]+a[1];
+}
+
+/* { dg-final { scan-tree-dump "Conditional store replacement" "cselim" } } */

gcc/testsuite/gcc.dg/tree-ssa/pr89430-2.c

+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-cselim-details" } */
+
+int c;
+unsigned test(unsigned k, unsigned b) {
+        unsigned a[2];
+	a[k] = c;
+        if (b < a[k]) {
+                a[k] = b;
+        }
+        return a[0]+a[1];
+}
+
+/* { dg-final { scan-tree-dump "Conditional store replacement" "cselim" } } */

gcc/testsuite/gcc.dg/tree-ssa/pr89430-3.c

+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-cselim-details" } */
+
+unsigned a[2];
+unsigned test(unsigned k, unsigned b) {
+        if (b < a[k]) {
+                a[k] = b;
+        }
+        return a[0]+a[1];
+}
+
+/* { dg-final { scan-tree-dump-not "Conditional store replacement" "cselim" } } */

gcc/testsuite/gcc.dg/tree-ssa/pr89430-4.c

+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-cselim-details" } */
+
+int *p;
+unsigned test(unsigned k, unsigned b) {
+        unsigned a[2];
+	p = a;
+        if (b < a[k]) {
+                a[k] = b;
+        }
+        return a[0]+a[1];
+}
+
+/* { dg-final { scan-tree-dump-not "Conditional store replacement" "cselim" } } */

gcc/testsuite/gcc.dg/tree-ssa/pr89430-5.c

+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-cselim-details" } */
+
+int test(int b, int k) {
+    struct {
+        int data[2];
+    } a;
+
+    if (b < a.data[k]) {
+        a.data[k] = b;
+    }
+
+    return a.data[0] + a.data[1];
+}
+
+/* { dg-final { scan-tree-dump "Conditional store replacement" "cselim" } } */

gcc/testsuite/gcc.dg/tree-ssa/pr89430-6.c

+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-cselim-details" } */
+
+int test(int b, int k) {
+    typedef struct {
+	    int x;
+    } SS;
+    struct {
+        SS data[2];
+    } a;
+
+    if (b < a.data[k].x) {
+        a.data[k].x = b;
+    }
+
+    return a.data[0].x + a.data[1].x;
+}
+
+/* { dg-final { scan-tree-dump "Conditional store replacement" "cselim" } } */

gcc/tree-ssa-phiopt.c

@@ -2196,7 +2196,8 @@ get_non_trapping (void)
 
    We check that MIDDLE_BB contains only one store, that that store
    doesn't trap (not via NOTRAP, but via checking if an access to the same
-   memory location dominates us) and that the store has a "simple" RHS.  */
+   memory location dominates us, or the store is to a local addressable
+   object) and that the store has a "simple" RHS.  */
 
 static bool
 cond_store_replacement (basic_block middle_bb, basic_block join_bb,
@@ -2218,8 +2219,9 @@ cond_store_replacement (basic_block middle_bb, basic_block join_bb,
   locus = gimple_location (assign);
   lhs = gimple_assign_lhs (assign);
   rhs = gimple_assign_rhs1 (assign);
-  if (TREE_CODE (lhs) != MEM_REF
-      || TREE_CODE (TREE_OPERAND (lhs, 0)) != SSA_NAME
+  if ((TREE_CODE (lhs) != MEM_REF
+       && TREE_CODE (lhs) != ARRAY_REF
+       && TREE_CODE (lhs) != COMPONENT_REF)
       || !is_gimple_reg_type (TREE_TYPE (lhs)))
     return false;
 
@@ -2227,7 +2229,13 @@ cond_store_replacement (basic_block middle_bb, basic_block join_bb,
      TREE_THIS_NOTRAP here, but in that case we also could move stores,
      whose value is not available readily, which we want to avoid.  */
   if (!nontrap->contains (lhs))
-    return false;
+    {
+      /* If LHS is a local variable without address-taken, we could
+	 always safely move down the store.  */
+      tree base = get_base_address (lhs);
+      if (!auto_var_p (base) || TREE_ADDRESSABLE (base))
+	return false;
+    }
 
   /* Now we've checked the constraints, so do the transformation:
      1) Remove the single store.  */
@@ -2280,6 +2288,14 @@ cond_store_replacement (basic_block middle_bb, basic_block join_bb,
   else
     gsi_insert_before (&gsi, new_stmt, GSI_NEW_STMT);
 
+  if (dump_file && (dump_flags & TDF_DETAILS))
+    {
+      fprintf (dump_file, "\nConditional store replacement happened!");
+      fprintf (dump_file, "\nReplaced the store with a load.");
+      fprintf (dump_file, "\nInserted a new PHI statement in joint block:\n");
+      print_gimple_stmt (dump_file, new_stmt, 0, TDF_VOPS|TDF_MEMSYMS);
+    }
+
   return true;
 }