[PATCH]AArch64 sve2: Fix expansion of division [PR107830]

[Tamar Christina <tamar.christina@arm.com>]

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Hi All,

SVE has an actual division optab, and when using -Os we don't
optimize the division away.  This means that we need to distinguish
between a div which we can optimize and one we cannot even during
expansion.

Bootstrapped Regtested on aarch64-none-linux-gnu and no issues.

Ok for master?

Thanks,
Tamar

gcc/ChangeLog:

	PR target/107830
	* config/aarch64/aarch64.cc
	(aarch64_vectorize_can_special_div_by_constant): Check validity during
	codegen phase as well.

gcc/testsuite/ChangeLog:

	PR target/107830
	* gcc.target/aarch64/sve2/pr107830.c: New test.

--- inline copy of patch -- 
diff --git a/gcc/config/aarch64/aarch64.cc b/gcc/config/aarch64/aarch64.cc
index 4176d7b046a126664360596b6db79a43e77ff76a..bee23625807af95d5ec15ad45702961b2d7ab55d 100644
--- a/gcc/config/aarch64/aarch64.cc
+++ b/gcc/config/aarch64/aarch64.cc
@@ -24322,12 +24322,15 @@ aarch64_vectorize_can_special_div_by_constant (enum tree_code code,
   if ((flags & VEC_ANY_SVE) && !TARGET_SVE2)
     return false;
 
+  wide_int val = wi::add (cst, 1);
+  int pow = wi::exact_log2 (val);
+  bool valid_p = pow == (int)(element_precision (vectype) / 2);
+  /* SVE actually has a div operator, we we may have gotten here through
+     that route.  */
   if (in0 == NULL_RTX && in1 == NULL_RTX)
-    {
-      wide_int val = wi::add (cst, 1);
-      int pow = wi::exact_log2 (val);
-      return pow == (int)(element_precision (vectype) / 2);
-    }
+    return valid_p;
+  else if (!valid_p)
+    return false;
 
   if (!VECTOR_TYPE_P (vectype))
    return false;
diff --git a/gcc/testsuite/gcc.target/aarch64/sve2/pr107830.c b/gcc/testsuite/gcc.target/aarch64/sve2/pr107830.c
new file mode 100644
index 0000000000000000000000000000000000000000..6d8ee3615fdb0083dbde1e45a2826fb681726139
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/sve2/pr107830.c
@@ -0,0 +1,13 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target fopenmp } */
+/* { dg-additional-options "-Os -fopenmp" } */
+
+void
+f2 (int *a)
+{
+  unsigned int i;
+
+#pragma omp simd
+  for (i = 0; i < 4; ++i)
+    a[i / 3] -= 4;
+}




-- 

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diff --git a/gcc/config/aarch64/aarch64.cc b/gcc/config/aarch64/aarch64.cc
index 4176d7b046a126664360596b6db79a43e77ff76a..bee23625807af95d5ec15ad45702961b2d7ab55d 100644
--- a/gcc/config/aarch64/aarch64.cc
+++ b/gcc/config/aarch64/aarch64.cc
@@ -24322,12 +24322,15 @@ aarch64_vectorize_can_special_div_by_constant (enum tree_code code,
   if ((flags & VEC_ANY_SVE) && !TARGET_SVE2)
     return false;
 
+  wide_int val = wi::add (cst, 1);
+  int pow = wi::exact_log2 (val);
+  bool valid_p = pow == (int)(element_precision (vectype) / 2);
+  /* SVE actually has a div operator, we we may have gotten here through
+     that route.  */
   if (in0 == NULL_RTX && in1 == NULL_RTX)
-    {
-      wide_int val = wi::add (cst, 1);
-      int pow = wi::exact_log2 (val);
-      return pow == (int)(element_precision (vectype) / 2);
-    }
+    return valid_p;
+  else if (!valid_p)
+    return false;
 
   if (!VECTOR_TYPE_P (vectype))
    return false;
diff --git a/gcc/testsuite/gcc.target/aarch64/sve2/pr107830.c b/gcc/testsuite/gcc.target/aarch64/sve2/pr107830.c
new file mode 100644
index 0000000000000000000000000000000000000000..6d8ee3615fdb0083dbde1e45a2826fb681726139
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/sve2/pr107830.c
@@ -0,0 +1,13 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target fopenmp } */
+/* { dg-additional-options "-Os -fopenmp" } */
+
+void
+f2 (int *a)
+{
+  unsigned int i;
+
+#pragma omp simd
+  for (i = 0; i < 4; ++i)
+    a[i / 3] -= 4;
+}