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* [PATCH] rs6000: Fix wrong align passed to build_aligned_type [PR88309]
@ 2024-04-08  9:22 Kewen.Lin
  2024-04-08 10:47 ` Richard Biener
  0 siblings, 1 reply; 4+ messages in thread
From: Kewen.Lin @ 2024-04-08  9:22 UTC (permalink / raw)
  To: GCC Patches
  Cc: Segher Boessenkool, David Edelsohn, Peter Bergner,
	Richard Biener, Andrew Pinski

Hi,

As the comments in PR88309 show, there are two oversights
in rs6000_gimple_fold_builtin that pass align in bytes to
build_aligned_type but which actually requires align in
bits, it causes unexpected ICE or hanging in function
is_miss_rate_acceptable due to zero align_unit value.

This patch is to fix them by converting bytes to bits, add
an assertion on positive align_unit value and notes function
build_aligned_type requires align measured in bits in its
function comment.

Bootstrapped and regtested on x86_64-redhat-linux, 
powerpc64-linux-gnu P8/P9 and powerpc64le-linux-gnu P9 and P10.

Is it (the generic part code change) ok for trunk?

BR,
Kewen
-----
	PR target/88309

Co-authored-by: Andrew Pinski <quic_apinski@quicinc.com>

gcc/ChangeLog:

	* config/rs6000/rs6000-builtin.cc (rs6000_gimple_fold_builtin): Fix
	wrong align passed to function build_aligned_type.
	* tree-ssa-loop-prefetch.cc (is_miss_rate_acceptable): Add an
	assertion to ensure align_unit should be positive.
	* tree.cc (build_qualified_type): Update function comments.

gcc/testsuite/ChangeLog:

	* gcc.target/powerpc/pr88309.c: New test.
---
 gcc/config/rs6000/rs6000-builtin.cc        |  4 ++--
 gcc/testsuite/gcc.target/powerpc/pr88309.c | 27 ++++++++++++++++++++++
 gcc/tree-ssa-loop-prefetch.cc              |  2 ++
 gcc/tree.cc                                |  3 ++-
 4 files changed, 33 insertions(+), 3 deletions(-)
 create mode 100644 gcc/testsuite/gcc.target/powerpc/pr88309.c

diff --git a/gcc/config/rs6000/rs6000-builtin.cc b/gcc/config/rs6000/rs6000-builtin.cc
index 6698274031b..e7d6204074c 100644
--- a/gcc/config/rs6000/rs6000-builtin.cc
+++ b/gcc/config/rs6000/rs6000-builtin.cc
@@ -1900,7 +1900,7 @@ rs6000_gimple_fold_builtin (gimple_stmt_iterator *gsi)
 	tree lhs_type = TREE_TYPE (lhs);
 	/* In GIMPLE the type of the MEM_REF specifies the alignment.  The
 	  required alignment (power) is 4 bytes regardless of data type.  */
-	tree align_ltype = build_aligned_type (lhs_type, 4);
+	tree align_ltype = build_aligned_type (lhs_type, 32);
 	/* POINTER_PLUS_EXPR wants the offset to be of type 'sizetype'.  Create
 	   the tree using the value from arg0.  The resulting type will match
 	   the type of arg1.  */
@@ -1944,7 +1944,7 @@ rs6000_gimple_fold_builtin (gimple_stmt_iterator *gsi)
 	tree arg2_type = ptr_type_node;
 	/* In GIMPLE the type of the MEM_REF specifies the alignment.  The
 	   required alignment (power) is 4 bytes regardless of data type.  */
-	tree align_stype = build_aligned_type (arg0_type, 4);
+	tree align_stype = build_aligned_type (arg0_type, 32);
 	/* POINTER_PLUS_EXPR wants the offset to be of type 'sizetype'.  Create
 	   the tree using the value from arg1.  */
 	gimple_seq stmts = NULL;
diff --git a/gcc/testsuite/gcc.target/powerpc/pr88309.c b/gcc/testsuite/gcc.target/powerpc/pr88309.c
new file mode 100644
index 00000000000..c0078cf2b8c
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/pr88309.c
@@ -0,0 +1,27 @@
+/* { dg-require-effective-target powerpc_vsx_ok } */
+/* { dg-options "-mvsx -O2 -fprefetch-loop-arrays" } */
+
+/* Verify there is no ICE or hanging.  */
+
+#include <altivec.h>
+
+void b(float *c, vector float a, vector float, vector float)
+{
+  vector float d;
+  vector char ahbc;
+  vec_xst(vec_perm(a, d, ahbc), 0, c);
+}
+
+vector float e(vector unsigned);
+
+void f() {
+  float *dst;
+  int g = 0;
+  for (;; g += 16) {
+    vector unsigned m, i;
+    vector unsigned n, j;
+    vector unsigned k, l;
+    b(dst + g * 3, e(m), e(n), e(k));
+    b(dst + (g + 4) * 3, e(i), e(j), e(l));
+  }
+}
diff --git a/gcc/tree-ssa-loop-prefetch.cc b/gcc/tree-ssa-loop-prefetch.cc
index bbd98e03254..70073cc4fe4 100644
--- a/gcc/tree-ssa-loop-prefetch.cc
+++ b/gcc/tree-ssa-loop-prefetch.cc
@@ -739,6 +739,8 @@ is_miss_rate_acceptable (unsigned HOST_WIDE_INT cache_line_size,
   if (delta >= (HOST_WIDE_INT) cache_line_size)
     return false;

+  gcc_assert (align_unit > 0);
+
   miss_positions = 0;
   total_positions = (cache_line_size / align_unit) * distinct_iters;
   max_allowed_miss_positions = (ACCEPTABLE_MISS_RATE * total_positions) / 1000;
diff --git a/gcc/tree.cc b/gcc/tree.cc
index f801712c9dd..6f8400e6640 100644
--- a/gcc/tree.cc
+++ b/gcc/tree.cc
@@ -5689,7 +5689,8 @@ build_qualified_type (tree type, int type_quals MEM_STAT_DECL)
   return t;
 }

-/* Create a variant of type T with alignment ALIGN.  */
+/* Create a variant of type T with alignment ALIGN which
+   is measured in bits.  */

 tree
 build_aligned_type (tree type, unsigned int align)
--
2.43.0

^ permalink raw reply	[flat|nested] 4+ messages in thread
end of thread, other threads:[~2024-04-09  6:55 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2024-04-08  9:22 [PATCH] rs6000: Fix wrong align passed to build_aligned_type [PR88309] Kewen.Lin
2024-04-08 10:47 ` Richard Biener
2024-04-09  2:07   ` Kewen.Lin
2024-04-09  6:55     ` Richard Biener

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