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Allow some NOP conversions in (X+CST1)+CST2 in match.pd
- From: Marc Glisse <marc dot glisse at inria dot fr>
- To: gcc-patches at gcc dot gnu dot org
- Date: Sun, 21 May 2017 21:22:56 +0200 (CEST)
- Subject: Allow some NOP conversions in (X+CST1)+CST2 in match.pd
- Authentication-results: sourceware.org; auth=none
Hello,
generalizing a bit one transformation, to avoid a regression with another
patch I am working on. Handling conversions always gets messy :-( It would
have been easier to stick to scalars and wide_int, but since the existing
transformation handles vectors, I didn't want to regress.
Bootstrap+testsuite on powerpc64le-unknown-linux-gnu.
2017-05-22 Marc Glisse <marc.glisse@inria.fr>
gcc/
* match.pd ((A +- CST1) +- CST2): Allow some conversions.
* tree.c (drop_tree_overflow): Handle COMPLEX_CST and VECTOR_CST.
gcc/testsuite/
* gcc.dg/tree-ssa/addadd.c: New file.
--
Marc Glisse
Index: match.pd
===================================================================
--- match.pd (revision 248312)
+++ match.pd (working copy)
@@ -1265,29 +1265,53 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
(simplify
(minus @0 (plus:c @0 @1))
(negate @1))
(simplify
(minus @0 (minus @0 @1))
@1)
/* (A +- CST1) +- CST2 -> A + CST3 */
(for outer_op (plus minus)
(for inner_op (plus minus)
+ neg_inner_op (minus plus)
(simplify
- (outer_op (inner_op @0 CONSTANT_CLASS_P@1) CONSTANT_CLASS_P@2)
- /* If the constant operation overflows we cannot do the transform
- as we would introduce undefined overflow, for example
- with (a - 1) + INT_MIN. */
- (with { tree cst = const_binop (outer_op == inner_op
- ? PLUS_EXPR : MINUS_EXPR, type, @1, @2); }
- (if (cst && !TREE_OVERFLOW (cst))
- (inner_op @0 { cst; } ))))))
+ (outer_op (convert? (inner_op @0 CONSTANT_CLASS_P@1)) CONSTANT_CLASS_P@2)
+ (if (tree_nop_conversion_p (type, TREE_TYPE (@0)))
+ /* If one of the types wraps, use that one. */
+ (if (!ANY_INTEGRAL_TYPE_P (type) || TYPE_OVERFLOW_WRAPS (type))
+ (if (outer_op == PLUS_EXPR)
+ (plus (convert @0) (inner_op @2 (convert @1)))
+ (minus (convert @0) (neg_inner_op @2 (convert @1))))
+ (if (!ANY_INTEGRAL_TYPE_P (TREE_TYPE (@0))
+ || TYPE_OVERFLOW_WRAPS (TREE_TYPE (@0)))
+ (if (outer_op == PLUS_EXPR)
+ (convert (plus @0 (inner_op (convert @2) @1)))
+ (convert (minus @0 (neg_inner_op (convert @2) @1))))
+ /* If the constant operation overflows we cannot do the transform
+ directly as we would introduce undefined overflow, for example
+ with (a - 1) + INT_MIN. */
+ (if (types_match (type, @0))
+ (with { tree cst = const_binop (outer_op == inner_op
+ ? PLUS_EXPR : MINUS_EXPR,
+ type, @1, @2); }
+ (if (cst && !TREE_OVERFLOW (cst))
+ (inner_op @0 { cst; } )
+ /* X+INT_MAX+1 is X-INT_MIN. */
+ (if (INTEGRAL_TYPE_P (type) && cst
+ && wi::eq_p (cst, wi::min_value (type)))
+ (neg_inner_op @0 { wide_int_to_tree (type, cst); })
+ /* Last resort, use some unsigned type. */
+ (with { tree utype = unsigned_type_for (type); }
+ (convert (inner_op
+ (convert:utype @0)
+ (convert:utype
+ { drop_tree_overflow (cst); }))))))))))))))
/* (CST1 - A) +- CST2 -> CST3 - A */
(for outer_op (plus minus)
(simplify
(outer_op (minus CONSTANT_CLASS_P@1 @0) CONSTANT_CLASS_P@2)
(with { tree cst = const_binop (outer_op, type, @1, @2); }
(if (cst && !TREE_OVERFLOW (cst))
(minus { cst; } @0)))))
/* CST1 - (CST2 - A) -> CST3 + A */
Index: testsuite/gcc.dg/tree-ssa/addadd.c
===================================================================
--- testsuite/gcc.dg/tree-ssa/addadd.c (nonexistent)
+++ testsuite/gcc.dg/tree-ssa/addadd.c (working copy)
@@ -0,0 +1,34 @@
+/* { dg-do compile } */
+/* { dg-options "-O -fdump-tree-optimized" } */
+
+int f(unsigned x){
+ x += 123;
+ int y = x;
+ y -= 99;
+ return y;
+}
+unsigned g(int x){
+ x += 123;
+ unsigned y = x;
+ y -= 99;
+ return y;
+}
+int h(int x){
+ x += __INT_MAX__;
+ x += 1;
+ return x;
+}
+int i(int x){
+ x += __INT_MAX__;
+ x += __INT_MAX__;
+ return x;
+}
+typedef int S __attribute__((vector_size(16)));
+void j(S*x){
+ *x += __INT_MAX__;
+ *x += __INT_MAX__;
+}
+
+/* { dg-final { scan-tree-dump-times " \\+ 24;" 2 "optimized" } } */
+/* { dg-final { scan-tree-dump-times "\\(unsigned int\\)" 2 "optimized" } } */
+/* { dg-final { scan-tree-dump-not "2147483647" "optimized" } } */
Index: tree.c
===================================================================
--- tree.c (revision 248312)
+++ tree.c (working copy)
@@ -13131,20 +13131,39 @@ drop_tree_overflow (tree t)
gcc_checking_assert (TREE_OVERFLOW (t));
/* For tree codes with a sharing machinery re-build the result. */
if (TREE_CODE (t) == INTEGER_CST)
return wide_int_to_tree (TREE_TYPE (t), t);
/* Otherwise, as all tcc_constants are possibly shared, copy the node
and drop the flag. */
t = copy_node (t);
TREE_OVERFLOW (t) = 0;
+
+ /* For constants that contain nested constants, drop the flag
+ from those as well. */
+ if (TREE_CODE (t) == COMPLEX_CST)
+ {
+ if (TREE_OVERFLOW (TREE_REALPART (t)))
+ TREE_REALPART (t) = drop_tree_overflow (TREE_REALPART (t));
+ if (TREE_OVERFLOW (TREE_IMAGPART (t)))
+ TREE_IMAGPART (t) = drop_tree_overflow (TREE_IMAGPART (t));
+ }
+ if (TREE_CODE (t) == VECTOR_CST)
+ {
+ for (unsigned i = 0; i < VECTOR_CST_NELTS (t); ++i)
+ {
+ tree& elt = VECTOR_CST_ELT (t, i);
+ if (TREE_OVERFLOW (elt))
+ elt = drop_tree_overflow (elt);
+ }
+ }
return t;
}
/* Given a memory reference expression T, return its base address.
The base address of a memory reference expression is the main
object being referenced. For instance, the base address for
'array[i].fld[j]' is 'array'. You can think of this as stripping
away the offset part from a memory address.
This function calls handled_component_p to strip away all the inner