Re: [PATCH] Use proper type in linear transformation in tree-switch-conversion (PR tree-optimization/88753).

["Martin Liška" <mliska@suse.cz>]

[-- Attachment #1: Type: text/plain, Size: 1254 bytes --]

On 1/8/19 1:52 PM, Jakub Jelinek wrote:
> On Tue, Jan 08, 2019 at 01:40:41PM +0100, Martin Liška wrote:
>> As seen in the PR, when doing switch convert linear transformation,
>> one needs to first convert to unsigned type for constructor values.
>>
>> Patch survives regression tests and bootstrap on x86_64-linux-gnu.
>> Ready for trunk?
>> Thanks,
>> Martin
>>
>>
>> gcc/ChangeLog:
>>
>> 2019-01-08  Martin Liska  <mliska@suse.cz>
>>
>> 	PR tree-optimization/88753
>> 	* tree-switch-conversion.c (switch_conversion::build_one_array):
>> 	Come up with local variable constructor.  Convert first to
>> 	type of constructor values.
> 
> Why is the testcase missing?

Because I forgot to call git add ;)

> 
> Otherwise LGTM.
> 
> Also, note contains_linear_function_p
>   wide_int range_min = wi::to_wide (fold_convert (TREE_TYPE (elt0),
>                                                   m_range_min));
> could be written on wide_ints directly:
>   wide_int range_min
>     = wide_int::from (wi::to_wide (m_range_min),
> 		      TYPE_PRECISION (TREE_TYPE (elt0)),
> 		      TYPE_SIGN (TREE_TYPE (m_range_min)));
> 
> 	Jakub
> 

Changed that. I verified that tree-ssa.exp tests work fine. May I install the hunk you suggested
without testing?

Martin

[-- Attachment #2: 0001-Use-proper-type-in-linear-transformation-in-tree-swi.patch --]
[-- Type: text/x-patch, Size: 4419 bytes --]

From 52f8961361f894cca35c616a38486f69c48c194c Mon Sep 17 00:00:00 2001
From: marxin <mliska@suse.cz>
Date: Tue, 8 Jan 2019 12:56:03 +0100
Subject: [PATCH] Use proper type in linear transformation in
 tree-switch-conversion (PR tree-optimization/88753).

gcc/ChangeLog:

2019-01-08  Martin Liska  <mliska@suse.cz>

	PR tree-optimization/88753
	* tree-switch-conversion.c (switch_conversion::build_one_array):
	Come up with local variable constructor.  Convert first to
	type of constructor values.

gcc/testsuite/ChangeLog:

2019-01-08  Martin Liska  <mliska@suse.cz>

	* gcc.dg/tree-ssa/pr88753.c: New test.
---
 gcc/testsuite/gcc.dg/tree-ssa/pr88753.c | 57 +++++++++++++++++++++++++
 gcc/tree-switch-conversion.c            | 17 +++++---
 2 files changed, 67 insertions(+), 7 deletions(-)
 create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr88753.c

diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr88753.c b/gcc/testsuite/gcc.dg/tree-ssa/pr88753.c
new file mode 100644
index 00000000000..eaefc38962f
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr88753.c
@@ -0,0 +1,57 @@
+/* PR tree-optimization/88753 */
+/* { dg-options "-O2 -fdump-tree-switchconv" } */
+/* { dg-do run { target nonpic } } */
+
+typedef unsigned short int uint16_t;
+typedef unsigned char uint8_t;
+
+uint16_t length;
+uint16_t enc_method_global;
+
+uint8_t
+__attribute__((noipa))
+_zip_buffer_get_8(int buffer)
+{
+  return buffer;
+}
+
+  int
+  __attribute__((noipa))
+foo(int v)
+{
+  uint16_t enc_method;
+  switch (_zip_buffer_get_8(v)) {
+    case 1:
+      enc_method = 0x0101;
+      break;
+    case 2:
+      enc_method = 0x0102;
+      break;
+    case 3:
+      enc_method = 0x0103;
+      break;
+    default:
+      __builtin_abort ();
+  }
+
+  enc_method_global = enc_method;
+}
+
+int main(int argc, char **argv)
+{
+  foo (1);
+  if (enc_method_global != 0x0101)
+    __builtin_abort ();
+
+  foo (2);
+  if (enc_method_global != 0x0102)
+    __builtin_abort ();
+
+  foo (3);
+  if (enc_method_global != 0x0103)
+    __builtin_abort ();
+
+  return 0;
+}
+
+/* { dg-final { scan-tree-dump-times "Linear transformation with A = 1 and B = 256" 1 "switchconv" } } */
diff --git a/gcc/tree-switch-conversion.c b/gcc/tree-switch-conversion.c
index 614c450dd4d..c3f2baf39d7 100644
--- a/gcc/tree-switch-conversion.c
+++ b/gcc/tree-switch-conversion.c
@@ -473,8 +473,10 @@ switch_conversion::contains_linear_function_p (vec<constructor_elt, va_gc> *vec,
   if (TREE_CODE (elt0) != INTEGER_CST || TREE_CODE (elt1) != INTEGER_CST)
     return false;
 
-  wide_int range_min = wi::to_wide (fold_convert (TREE_TYPE (elt0),
-						  m_range_min));
+  wide_int range_min
+    = wide_int::from (wi::to_wide (m_range_min),
+		      TYPE_PRECISION (TREE_TYPE (elt0)),
+		      TYPE_SIGN (TREE_TYPE (m_range_min)));
   wide_int y1 = wi::to_wide (elt0);
   wide_int y2 = wi::to_wide (elt1);
   wide_int a = y2 - y1;
@@ -600,9 +602,9 @@ switch_conversion::build_one_array (int num, tree arr_index_type,
   name = copy_ssa_name (PHI_RESULT (phi));
   m_target_inbound_names[num] = name;
 
+  vec<constructor_elt, va_gc> *constructor = m_constructors[num];
   wide_int coeff_a, coeff_b;
-  bool linear_p = contains_linear_function_p (m_constructors[num], &coeff_a,
-					      &coeff_b);
+  bool linear_p = contains_linear_function_p (constructor, &coeff_a, &coeff_b);
   if (linear_p)
     {
       if (dump_file && coeff_a.to_uhwi () > 0)
@@ -610,7 +612,8 @@ switch_conversion::build_one_array (int num, tree arr_index_type,
 		 " and B = %" PRId64 "\n", coeff_a.to_shwi (),
 		 coeff_b.to_shwi ());
 
-      tree t = unsigned_type_for (TREE_TYPE (m_index_expr));
+      /* We must use type of constructor values.  */
+      tree t = unsigned_type_for (TREE_TYPE ((*constructor)[0].value));
       gimple_seq seq = NULL;
       tree tmp = gimple_convert (&seq, t, m_index_expr);
       tree tmp2 = gimple_build (&seq, MULT_EXPR, t,
@@ -633,10 +636,10 @@ switch_conversion::build_one_array (int num, tree arr_index_type,
 	  unsigned int i;
 	  constructor_elt *elt;
 
-	  FOR_EACH_VEC_SAFE_ELT (m_constructors[num], i, elt)
+	  FOR_EACH_VEC_SAFE_ELT (constructor, i, elt)
 	    elt->value = fold_convert (value_type, elt->value);
 	}
-      ctor = build_constructor (array_type, m_constructors[num]);
+      ctor = build_constructor (array_type, constructor);
       TREE_CONSTANT (ctor) = true;
       TREE_STATIC (ctor) = true;
 
-- 
2.20.1