Hello,
this patch does 2 things (I should have split it in 2, but the questions
go together):
1) it handles constant folding of vector comparisons,
2) it fixes another place where vectors are not expected (I'll probably
wait to have front-end support and testcases to do more of those, but
there is something to discuss).
I wasn't sure what integer_truep should test exactly. For integer: == 1 or
!= 0? For vectors: == -1 or < 0? I chose the one that worked best for the
forwprop case where I used it.
It seems that before this patch, the middle-end didn't know how comparison
results were encoded (a good reason for VEC_COND_EXPR to require a
comparison as its first argument). I am using the OpenCL encoding that
what matters is the high bit of each vector element. I am not quite sure
what happens for targets (are there any?) that use a different encoding.
When expanding vcond, they can do the comparison as they like. When
expanding an isolated comparison, I expect they have to expand it as
vcond(a<b,-1,0). So it should be ok, but I could easily have missed
something.
2012-10-01 Marc Glisse <marc.gli...@inria.fr>
gcc/
* tree.c (integer_truep): New function.
* tree.h (integer_truep): Declare.
* tree-ssa-forwprop.c (forward_propagate_into_cond): Call it.
Don't use boolean_type_node for vectors.
* fold-const.c (fold_relational_const): Handle VECTOR_CST.
gcc/testsuite/
* gcc.dg/tree-ssa/foldconst-6.c: New testcase.
--
Marc GlisseIndex: gcc/tree.h
===================================================================
--- gcc/tree.h (revision 191850)
+++ gcc/tree.h (working copy)
@@ -5272,20 +5272,25 @@ extern int integer_zerop (const_tree);
/* integer_onep (tree x) is nonzero if X is an integer constant of value 1. */
extern int integer_onep (const_tree);
/* integer_all_onesp (tree x) is nonzero if X is an integer constant
all of whose significant bits are 1. */
extern int integer_all_onesp (const_tree);
+/* integer_truep (tree x) is nonzero if X is an integer constant of value 1,
+ or a vector constant of value < 0. */
+
+extern bool integer_truep (const_tree);
+
/* integer_pow2p (tree x) is nonzero is X is an integer constant with
exactly one bit 1. */
extern int integer_pow2p (const_tree);
/* integer_nonzerop (tree x) is nonzero if X is an integer constant
with a nonzero value. */
extern int integer_nonzerop (const_tree);
Index: gcc/tree-ssa-forwprop.c
===================================================================
--- gcc/tree-ssa-forwprop.c (revision 191850)
+++ gcc/tree-ssa-forwprop.c (working copy)
@@ -564,46 +564,46 @@ forward_propagate_into_cond (gimple_stmt
enum tree_code code;
tree name = cond;
gimple def_stmt = get_prop_source_stmt (name, true, NULL);
if (!def_stmt || !can_propagate_from (def_stmt))
return 0;
code = gimple_assign_rhs_code (def_stmt);
if (TREE_CODE_CLASS (code) == tcc_comparison)
tmp = fold_build2_loc (gimple_location (def_stmt),
code,
- boolean_type_node,
+ TREE_TYPE (cond),
gimple_assign_rhs1 (def_stmt),
gimple_assign_rhs2 (def_stmt));
else if ((code == BIT_NOT_EXPR
&& TYPE_PRECISION (TREE_TYPE (cond)) == 1)
|| (code == BIT_XOR_EXPR
- && integer_onep (gimple_assign_rhs2 (def_stmt))))
+ && integer_truep (gimple_assign_rhs2 (def_stmt))))
{
tmp = gimple_assign_rhs1 (def_stmt);
swap = true;
}
}
if (tmp
&& is_gimple_condexpr (tmp))
{
if (dump_file && tmp)
{
fprintf (dump_file, " Replaced '");
print_generic_expr (dump_file, cond, 0);
fprintf (dump_file, "' with '");
print_generic_expr (dump_file, tmp, 0);
fprintf (dump_file, "'\n");
}
- if (integer_onep (tmp))
+ if (integer_truep (tmp))
gimple_assign_set_rhs_from_tree (gsi_p, gimple_assign_rhs2 (stmt));
else if (integer_zerop (tmp))
gimple_assign_set_rhs_from_tree (gsi_p, gimple_assign_rhs3 (stmt));
else
{
gimple_assign_set_rhs1 (stmt, unshare_expr (tmp));
if (swap)
{
tree t = gimple_assign_rhs2 (stmt);
gimple_assign_set_rhs2 (stmt, gimple_assign_rhs3 (stmt));
Index: gcc/testsuite/gcc.dg/tree-ssa/foldconst-6.c
===================================================================
--- gcc/testsuite/gcc.dg/tree-ssa/foldconst-6.c (revision 0)
+++ gcc/testsuite/gcc.dg/tree-ssa/foldconst-6.c (revision 0)
@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+/* { dg-options "-O -fdump-tree-ccp1" } */
+
+typedef long vec __attribute__ ((vector_size (2 * sizeof(long))));
+
+vec f ()
+{
+ vec a = { -2, 666 };
+ vec b = { 3, 2 };
+ return a < b;
+}
+
+/* { dg-final { scan-tree-dump-not "666" "ccp1"} } */
+/* { dg-final { cleanup-tree-dump "ccp1" } } */
Property changes on: gcc/testsuite/gcc.dg/tree-ssa/foldconst-6.c
___________________________________________________________________
Added: svn:keywords
+ Author Date Id Revision URL
Added: svn:eol-style
+ native
Index: gcc/fold-const.c
===================================================================
--- gcc/fold-const.c (revision 191850)
+++ gcc/fold-const.c (working copy)
@@ -16084,20 +16084,44 @@ fold_relational_const (enum tree_code co
TREE_IMAGPART (op0),
TREE_IMAGPART (op1));
if (code == EQ_EXPR)
return fold_build2 (TRUTH_ANDIF_EXPR, type, rcond, icond);
else if (code == NE_EXPR)
return fold_build2 (TRUTH_ORIF_EXPR, type, rcond, icond);
else
return NULL_TREE;
}
+ if (TREE_CODE (op0) == VECTOR_CST && TREE_CODE (op1) == VECTOR_CST)
+ {
+ int count = VECTOR_CST_NELTS (op0);
+ tree *elts = XALLOCAVEC (tree, count);
+ gcc_assert (TREE_CODE (type) == VECTOR_TYPE);
+
+ for (int i = 0; i < count; i++)
+ {
+ tree elem_type = TREE_TYPE (type);
+ tree elem0 = VECTOR_CST_ELT (op0, i);
+ tree elem1 = VECTOR_CST_ELT (op1, i);
+
+ elts[i] = fold_relational_const (code, elem_type,
+ elem0, elem1);
+
+ if(elts[i] == NULL_TREE)
+ return NULL_TREE;
+
+ elts[i] = fold_negate_const (elts[i], elem_type);
+ }
+
+ return build_vector (type, elts);
+ }
+
/* From here on we only handle LT, LE, GT, GE, EQ and NE.
To compute GT, swap the arguments and do LT.
To compute GE, do LT and invert the result.
To compute LE, swap the arguments, do LT and invert the result.
To compute NE, do EQ and invert the result.
Therefore, the code below must handle only EQ and LT. */
if (code == LE_EXPR || code == GT_EXPR)
Index: gcc/tree.c
===================================================================
--- gcc/tree.c (revision 191850)
+++ gcc/tree.c (working copy)
@@ -1835,20 +1835,48 @@ integer_all_onesp (const_tree expr)
else
high_value = ((HOST_WIDE_INT) 1 << shift_amount) - 1;
return (TREE_INT_CST_LOW (expr) == ~(unsigned HOST_WIDE_INT) 0
&& TREE_INT_CST_HIGH (expr) == high_value);
}
else
return TREE_INT_CST_LOW (expr) == ((unsigned HOST_WIDE_INT) 1 << prec) - 1;
}
+/* Return true if EXPR is an integer constant representing true. */
+
+bool
+integer_truep (const_tree expr)
+{
+ STRIP_NOPS (expr);
+
+ switch (TREE_CODE (expr))
+ {
+ case INTEGER_CST:
+ /* Do not just test != 0, some places expect the value 1. */
+ return (TREE_INT_CST_LOW (expr) == 1
+ && TREE_INT_CST_HIGH (expr) == 0);
+ case VECTOR_CST:
+ {
+ for (unsigned i = 0; i < VECTOR_CST_NELTS (expr); ++i)
+ {
+ tree elm = VECTOR_CST_ELT (expr, i);
+ if (TREE_CODE (elm) != INTEGER_CST || !tree_int_cst_sign_bit (elm))
+ return false;
+ }
+ return true;
+ }
+ default:
+ return false;
+ }
+}
+
/* Return 1 if EXPR is an integer constant that is a power of 2 (i.e., has only
one bit on). */
int
integer_pow2p (const_tree expr)
{
int prec;
unsigned HOST_WIDE_INT high, low;
STRIP_NOPS (expr);
