re PR tree-optimization/77848 (Gimple if-conversion results in redundant comparisons)

[gcc]

2016-11-17  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
            Richard Biener  <rguenther@suse.de>

	PR tree-optimization/77848
	* tree-if-conv.c (tree_if_conversion): Always version loops unless
	the user specified -ftree-loop-if-convert.

[gcc/testsuite]

2016-11-17  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
            Richard Biener  <rguenther@suse.de>

	PR tree-optimization/77848
	* gfortran.dg/vect/pr77848.f: New test.


Co-Authored-By: Richard Biener <rguenther@suse.de>

From-SVN: r242550

gcc/ChangeLog

+2016-11-17  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
+            Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/77848
+	* tree-if-conv.c (tree_if_conversion): Always version loops unless
+	the user specified -ftree-loop-if-convert.
+
 2016-11-17  Bernd Edlinger  <bernd.edlinger@hotmail.de>
 
 	PR target/77308
@@ -116,6 +123,7 @@
 	* rtl.h: Declare gt_ggc_mx and gt_pch_nx.
 
 2016-11-16  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
+	    Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/77848
 	* tree-if-conv.c (version_loop_for_if_conversion): When versioning

gcc/testsuite/ChangeLog

+2016-11-17  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
+            Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/77848
+	* gfortran.dg/vect/pr77848.f: New test.
+
 2016-11-17  Bernd Edlinger  <bernd.edlinger@hotmail.de>
 
 	PR target/77308

gcc/testsuite/gfortran.dg/vect/pr77848.f

+! PR 77848: Verify versioning is on when vectorization fails
+! { dg-do compile }
+! { dg-options "-O3 -ffast-math -fdump-tree-ifcvt -fdump-tree-vect-details" }
+
+      subroutine sub(x,a,n,m)
+      implicit none
+      real*8 x(*),a(*),atemp
+      integer i,j,k,m,n
+      real*8 s,t,u,v
+      do j=1,m
+         atemp=0.d0
+         do i=1,n
+            if (abs(a(i)).gt.atemp) then
+               atemp=a(i)
+               k = i
+            end if
+         enddo
+         call dummy(atemp,k)
+      enddo
+      return
+      end
+
+! { dg-final { scan-tree-dump "LOOP_VECTORIZED" "ifcvt" } }
+! { dg-final { scan-tree-dump "vectorized 0 loops in function" "vect" } }

gcc/tree-if-conv.c

@@ -2803,10 +2803,12 @@ tree_if_conversion (struct loop *loop)
 	  || loop->dont_vectorize))
     goto cleanup;
 
-  /* Either version this loop, or if the pattern is right for outer-loop
-     vectorization, version the outer loop.  In the latter case we will
-     still if-convert the original inner loop.  */
-  if ((any_pred_load_store || any_complicated_phi)
+  /* Since we have no cost model, always version loops unless the user
+     specified -ftree-loop-if-convert.  Either version this loop, or if
+     the pattern is right for outer-loop vectorization, version the
+     outer loop.  In the latter case we will still if-convert the
+     original inner loop.  */
+  if (flag_tree_loop_if_convert != 1
       && !version_loop_for_if_conversion
       (versionable_outer_loop_p (loop_outer (loop))
        ? loop_outer (loop) : loop))