diff mbox

[gomp4] improve collapse user var calculation

Message ID 122cae2f-fcc2-30d2-2c25-e53ee99bf966@acm.org
State New
Headers show

Commit Message

Nathan Sidwell Sept. 30, 2016, 12:19 p.m. UTC 
In working on tile I noticed an unnecessary modulo operation for the calculation 
of the outermost loop's user iteration variable.  By construction the modulo 
operator is useless here.  Took the opportunity of moving the modulo and 
division operations next to eachother so it'd be easier to make use of any 
divmod apparatus the target may have.

committed to gomp4.

nathan
diff mbox

Patch

2016-09-30  Nathan Sidwell  <nathan@codesourcery.com>

	* omp-low.c (expand_oacc_collapse_vars): Avoid DIV for outermost
	collaps var.

Index: omp-low.c
===================================================================
--- omp-low.c	(revision 240653)
+++ omp-low.c	(working copy)
@@ -7591,8 +7591,16 @@  expand_oacc_collapse_vars (const struct
 	  plus_type = sizetype;
 	}
 
-      expr = fold_build2 (TRUNC_MOD_EXPR, ivar_type, ivar,
-			  fold_convert (ivar_type, collapse->iters));
+      expr = ivar;
+      if (ix)
+	{
+	  tree mod = fold_convert (ivar_type, collapse->iters);
+	  ivar = fold_build2 (TRUNC_DIV_EXPR, ivar_type, expr, mod);
+	  expr = fold_build2 (TRUNC_MOD_EXPR, ivar_type, expr, mod);
+	  ivar = force_gimple_operand_gsi (gsi, ivar, true, NULL_TREE,
+					   true, GSI_SAME_STMT);
+	}
+      
       expr = fold_build2 (MULT_EXPR, diff_type, fold_convert (diff_type, expr),
 			  collapse->step);
       expr = fold_build2 (plus_code, iter_type, collapse->base,
@@ -7601,14 +7609,6 @@  expand_oacc_collapse_vars (const struct
 				       true, GSI_SAME_STMT);
       gassign *ass = gimple_build_assign (loop->v, expr);
       gsi_insert_before (gsi, ass, GSI_SAME_STMT);
-
-      if (ix)
-	{
-	  expr = fold_build2 (TRUNC_DIV_EXPR, ivar_type, ivar,
-			      fold_convert (ivar_type, collapse->iters));
-	  ivar = force_gimple_operand_gsi (gsi, expr, true, NULL_TREE,
-					   true, GSI_SAME_STMT);
-	}
     }
 }