middle-end: Add MULT_EXPR recognition for cond scalar reduction

gcc/ChangeLog:

	* tree-if-conv.cc (is_cond_scalar_reduction): Add MULT_EXPR
	recognition.

gcc/testsuite/ChangeLog:

	* gcc.dg/tree-ssa/gen-vect-34.c: New test.
	* gcc.dg/vect/vect-ifcvt-18.c: New test.

gcc/testsuite/gcc.dg/tree-ssa/gen-vect-34.c

@@ -0,0 +1,16 @@
+/* { dg-do compile } */
+/* { dg-options "-Ofast -fdump-tree-vect-details" } */
+/* { dg-additional-options "-mavx2" { target { x86_64-*-* i?86-*-* } } } */
+
+float summul(int n, float *arg1, float *arg2)
+{                                                  
+    int i;                                             
+    float res1 = 1.0;
+    for(i = 0; i < n; i++) {
+      if(arg2[i]) 
+        res1 *= arg1[i];
+    }                                                  
+    return res1;                                       
+}
+
+/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" { target { ! { avr-*-* pru-*-* } } } } } */

gcc/testsuite/gcc.dg/vect/vect-ifcvt-18.c

@@ -0,0 +1,38 @@
+/* { dg-require-effective-target vect_condition } */
+/* { dg-require-effective-target vect_float } */
+/* { dg-additional-options "-Ofast -mavx" { target avx_runtime } } */
+
+
+int A0[4] = {36,39,42,45};
+int B0[4] = {42,42,0,42};
+float A1[8] = {36,39,42,45,43,32,21,12};
+float B1[8] = {42,42,0,42,42,42,0,42};
+double A2[16] = {36,39,42,45,43,32,21,12,23,34,45,56,42,78,89,11};
+double B2[16] = {42,42,0,42,42,42,42,42,42,42,42,42,0,42,42,42};
+
+int main ()
+{
+  int i, j;
+  int res0 = 1;
+  float res1 = 1.0;
+  double res2 = 1.0;
+
+  for (i = 0; i < 4; i++)
+    if (B0[i])
+      res0 *= A0[i];
+
+  for (i = 0; i < 8; i++)
+    if (B1[i])
+      res1 *= A1[i];
+  
+  for (i = 0; i < 16; i++)
+    if (B2[i])
+      res2 *= A2[i];
+  /* check results:  */
+  if (res0 != 63180 || res1 != 1043228160.000000
+      ||res2 != 3296728515318523101184.000000)
+      __builtin_abort ();
+  return 0;
+}
+
+/* { dg-final { scan-tree-dump "vectorized 3 loops" "vect" { target i?86-*-* x86_64-*-* } } } */

gcc/tree-if-conv.cc

@@ -1739,6 +1739,7 @@ is_cond_scalar_reduction (gimple *phi, gimple **reduc, tree arg_0, tree arg_1,
 
   if (reduction_op != PLUS_EXPR
       && reduction_op != MINUS_EXPR
+      && reduction_op != MULT_EXPR
       && reduction_op != BIT_IOR_EXPR
       && reduction_op != BIT_XOR_EXPR
       && reduction_op != BIT_AND_EXPR)