re PR tree-optimization/15255 ([tree-ssa] a * 2 + a * 2 is not converted to a * 4)

2008-08-13  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/15255
	* tree-ssa-reassoc.c (linearize_expr_tree): Declare.
	(struct oecount_s): New struct and VEC types.
	(cvec): New global.
	(oecount_hash): New function.
	(oecount_eq): Likewise.
	(oecount_cmp): Likewise.
	(zero_one_operation): New function.
	(build_and_add_sum): Likewise.
	(undistribute_ops_list): Perform un-distribution of multiplication
	and division on the chain of summands.
	(should_break_up_subtract): Also break up subtracts for factors.
	(reassociate_bb): Delete dead visited statements.
	Call undistribute_ops_list.  Re-sort and optimize if it did something.
	* passes.c (init_optimization_passes): Move DSE before
	reassociation.
	* tree-ssa-loop-niter.c (stmt_dominates_stmt_p): Correctly handle
	PHI nodes.

	* gcc.dg/tree-ssa/reassoc-14.c: New testcase.
	* gcc.dg/tree-ssa/reassoc-15.c: Likewise.
	* gcc.dg/tree-ssa/reassoc-16.c: Likewise.
	* gcc.dg/torture/reassoc-1.c: Likewise.
	* gcc.dg/tree-ssa/recip-2.c: Adjust.
	* gcc.dg/tree-ssa/recip-6.c: Likewise.
	* gcc.dg/tree-ssa/recip-7.c: Likewise.
	* gfortran.dg/reassoc_4.f: Likewise.

From-SVN: r139048

gcc/ChangeLog

+2008-08-13  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/15255
+	* tree-ssa-reassoc.c (linearize_expr_tree): Declare.
+	(struct oecount_s): New struct and VEC types.
+	(cvec): New global.
+	(oecount_hash): New function.
+	(oecount_eq): Likewise.
+	(oecount_cmp): Likewise.
+	(zero_one_operation): New function.
+	(build_and_add_sum): Likewise.
+	(undistribute_ops_list): Perform un-distribution of multiplication
+	and division on the chain of summands.
+	(should_break_up_subtract): Also break up subtracts for factors.
+	(reassociate_bb): Delete dead visited statements.
+	Call undistribute_ops_list.  Re-sort and optimize if it did something.
+	* passes.c (init_optimization_passes): Move DSE before
+	reassociation.
+	* tree-ssa-loop-niter.c (stmt_dominates_stmt_p): Correctly handle
+	PHI nodes.
+
 2008-08-12  Janis Johnson  <janis187@us.ibm.com>
 
 	* doc/invoke.texi (-fipa-pta): Say the option is experimental.

gcc/passes.c

@@ -633,9 +633,9 @@ init_optimization_passes (void)
 	 only examines PHIs to discover const/copy propagation
 	 opportunities.  */
       NEXT_PASS (pass_phi_only_cprop);
+      NEXT_PASS (pass_dse);
       NEXT_PASS (pass_reassoc);
       NEXT_PASS (pass_dce);
-      NEXT_PASS (pass_dse);
       NEXT_PASS (pass_forwprop);
       NEXT_PASS (pass_phiopt);
       NEXT_PASS (pass_object_sizes);

gcc/testsuite/ChangeLog

+2008-08-13  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/15255
+	* gcc.dg/tree-ssa/reassoc-14.c: New testcase.
+	* gcc.dg/tree-ssa/reassoc-15.c: Likewise.
+	* gcc.dg/tree-ssa/reassoc-16.c: Likewise.
+	* gcc.dg/torture/reassoc-1.c: Likewise.
+	* gcc.dg/tree-ssa/recip-2.c: Adjust.
+	* gcc.dg/tree-ssa/recip-6.c: Likewise.
+	* gcc.dg/tree-ssa/recip-7.c: Likewise.
+	* gfortran.dg/reassoc_4.f: Likewise.
+
 2008-08-12  Janis Johnson  <janis187@us.ibm.com>
 
 	* gcc.target/i386/pr32000-2.c: Use dg-skip-if for target expression.

gcc/testsuite/gcc.dg/torture/reassoc-1.c

+/* { dg-do run } */
+
+int x;
+
+int __attribute__((noinline))
+foo(int a, int b, int w)
+{
+  int tmp1 = a * w;
+  int tmp2 = b * w;
+  x = tmp1;
+  return tmp1 + tmp2;
+}
+
+extern void abort (void);
+
+int main()
+{
+  if (foo(1, 2, 3) != 9)
+    abort ();
+  if (x != 3)
+    abort ();
+  return 0;
+}
+

gcc/testsuite/gcc.dg/tree-ssa/reassoc-14.c

+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-reassoc1" } */
+
+int test1 (int x, int y, int z, int weight)
+{
+  int tmp1 = x * weight;
+  int tmp2 = y * weight;
+  int tmp3 = (x - y) * weight;
+  return tmp1 + (tmp2 + tmp3);
+}
+
+int test2 (int x, int y, int z, int weight)
+{
+  int tmp1 = x * weight;
+  int tmp2 = y * weight * weight;
+  int tmp3 = z * weight * weight * weight;
+  return tmp1 + tmp2 + tmp3;
+}
+
+/* There should be one multiplication left in test1 and three in test2.  */
+
+/* { dg-final { scan-tree-dump-times "\\\*" 4 "reassoc1" } } */
+/* { dg-final { cleanup-tree-dump "reassoc1" } } */

gcc/testsuite/gcc.dg/tree-ssa/reassoc-15.c

+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-reassoc1" } */
+
+int test3 (int x, int y, int z, int weight, int w1, int w2, int w3)
+{
+  int wtmp1 = w1 * weight;
+  int wtmp2 = w2 * weight;
+  int wtmp3 = w3 * weight;
+  int tmp1 = x * wtmp1;
+  int tmp2 = y * wtmp2;
+  int tmp3 = z * wtmp3;
+  return tmp1 + tmp2 + tmp3;
+}
+
+/* The multiplication with weight should be un-distributed.
+   ???  This pattern is not recognized currently.  */
+
+/* { dg-final { scan-tree-dump-times "\\\*" 4 "reassoc1" } } */
+/* { dg-final { cleanup-tree-dump "reassoc1" } } */

gcc/testsuite/gcc.dg/tree-ssa/reassoc-16.c

+/* { dg-do compile } */
+/* { dg-options "-O2 -ffast-math -fdump-tree-reassoc1" } */
+
+double test1 (double x, double y, double z, double weight)
+{
+  double tmp1 = x / weight;
+  double tmp2 = y / weight;
+  double tmp3 = -x / weight;
+  return tmp1 + tmp2 + tmp3;
+}
+
+/* The division should be un-distributed and all references to x should
+   be gone.  */
+
+/* { dg-final { scan-tree-dump-times "/" 1 "reassoc1" } } */
+/* { dg-final { cleanup-tree-dump "reassoc1" } } */

gcc/testsuite/gcc.dg/tree-ssa/reassoc-17.c

+/* { dg-do compile } */
+/* { dg-options "-O2 -ffast-math -fdump-tree-reassoc1" } */
+
+double test2 (double x, double y, double ddj, int b)
+{
+  double tmp1, tmp2, sum;
+  sum = 0.0;
+  if (b)
+    sum = 1.0;
+  tmp1 = sum/ddj;
+  tmp2 = x/ddj;
+  return tmp1 + y + tmp2;
+}
+
+/* { dg-final { scan-tree-dump-times "/" 1 "reassoc1" } } */
+/* { dg-final { cleanup-tree-dump "reassoc1" } } */

gcc/testsuite/gcc.dg/tree-ssa/reassoc-18.c

+/* { dg-do compile } */
+/* { dg-options "-O -fdump-tree-reassoc1" } */
+
+int
+ETree_nFactorEntriesInFront (int b, int m)
+{
+  int nent = b*b + 2*b*m;
+  return nent;
+}
+
+/* { dg-final { scan-tree-dump-times "\\\*" 2 "reassoc1" } } */
+/* { dg-final { cleanup-tree-dump "reassoc1" } } */

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

 /* { dg-do compile } */
 /* { dg-options "-O1 -funsafe-math-optimizations -fdump-tree-recip" } */
 
-float e(float a, float b, float c, float d, float e, float f)
+float u, v, w, x, y, z;
+
+void e(float a, float b, float c, float d, float e, float f)
 {
   if (a < b)
     {
@@ -20,7 +22,12 @@ float e(float a, float b, float c, float d, float e, float f)
   /* This should not be left as a multiplication.  */
   c = 1 / c;
 
-  return a + b + c + d + e + f;
+  u = a;
+  v = b;
+  w = c;
+  x = d;
+  y = e;
+  z = f;
 }
 
 /* { dg-final { scan-tree-dump-times " / " 2 "recip" } } */

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

@@ -5,7 +5,9 @@
 
 extern int f2();
 
-double f1(double y, double z, double w)
+double m, n, o;
+
+void f1(double y, double z, double w)
 {
   double b, c, d, e, f;
 
@@ -18,7 +20,9 @@ double f1(double y, double z, double w)
   e = c / y;
   f = 1 / y;
 
-  return d + e + f;
+  m = d;
+  n = e;
+  o = f;
 }
 
 /* { dg-final { scan-tree-dump-times " / " 1 "recip" } } */

gcc/testsuite/gcc.dg/tree-ssa/recip-7.c

@@ -5,7 +5,9 @@
 
 extern double h();
 
-double f(int x, double z, double w)
+double m, n, o;
+
+void f(int x, double z, double w)
 {
   double b, c, d, e, f;
   double y = h ();
@@ -19,7 +21,9 @@ double f(int x, double z, double w)
   e = c / y;
   f = 1 / y;
 
-  return d + e + f;
+  m = d;
+  n = e;
+  o = f;
 }
 
 /* { dg-final { scan-tree-dump-times " / " 1 "recip" } } */

gcc/testsuite/gfortran.dg/reassoc_4.f

+! { dg-do compile }
+! { dg-options "-O3 -ffast-math -fdump-tree-reassoc1" }
+      subroutine anisonl(w,vo,anisox,s,ii1,jj1,weight)
+      integer ii1,jj1,i1,iii1,j1,jjj1,k1,l1,m1,n1
+      real*8 w(3,3),vo(3,3),anisox(3,3,3,3),s(60,60),weight
+!
+!     This routine replaces the following lines in e_c3d.f for
+!     an anisotropic material
+!
+                      do i1=1,3
+                        iii1=ii1+i1-1
+                        do j1=1,3
+                          jjj1=jj1+j1-1
+                          do k1=1,3
+                            do l1=1,3
+                              s(iii1,jjj1)=s(iii1,jjj1)
+     &                          +anisox(i1,k1,j1,l1)*w(k1,l1)*weight
+                              do m1=1,3
+                                s(iii1,jjj1)=s(iii1,jjj1)
+     &                              +anisox(i1,k1,m1,l1)*w(k1,l1)
+     &                                 *vo(j1,m1)*weight
+     &                              +anisox(m1,k1,j1,l1)*w(k1,l1)
+     &                                 *vo(i1,m1)*weight
+                                do n1=1,3
+                                  s(iii1,jjj1)=s(iii1,jjj1)
+     &                              +anisox(m1,k1,n1,l1)
+     &                              *w(k1,l1)*vo(i1,m1)*vo(j1,n1)*weight
+                                enddo
+                              enddo
+                            enddo
+                          enddo
+                        enddo
+                      enddo
+
+      return
+      end
+
+! There should be 22 multiplications left after un-distributing
+! weigth, w(k1,l1), vo(i1,m1) and vo(j1,m1) on the innermost two
+! unrolled loops.
+
+! { dg-final { scan-tree-dump-times "\[0-9\] \\\* " 22 "reassoc1" } }
+! { dg-final { cleanup-tree-dump "reassoc1" } }

gcc/tree-ssa-loop-niter.c

@@ -2914,6 +2914,12 @@ stmt_dominates_stmt_p (gimple s1, gimple s2)
     {
       gimple_stmt_iterator bsi;
 
+      if (gimple_code (s2) == GIMPLE_PHI)
+	return false;
+
+      if (gimple_code (s1) == GIMPLE_PHI)
+	return true;
+
       for (bsi = gsi_start_bb (bb1); gsi_stmt (bsi) != s2; gsi_next (&bsi))
 	if (gsi_stmt (bsi) == s1)
 	  return true;