On Fri, 6 May 2016, Marc Glisse wrote:
Here they are. I did (X&Y)&X and (X&Y)&(X&Z). The next one would be
((X&Y)&Z)&X, but at some point we have to defer to reassoc.
I didn't add the convert?+tree_nop_conversion_p to the existing transform I
modified. I guess at some point we should make a pass and add them to all the
transformations on bit operations...
For (X & Y) & Y, I believe that any conversion is fine. For the others,
tree_nop_conversion_p is probably too strict (narrowing should be fine for
all), but I was too lazy to look for tighter conditions.
(X ^ Y) ^ Y -> X should probably have (non_lvalue ...) on its output, but in
a simple test it didn't seem to matter. Is non_lvalue still needed?
Bootstrap+regtest on powerpc64le-unknown-linux-gnu.
2016-05-06 Marc Glisse <marc.gli...@inria.fr>
gcc/
* fold-const.c (fold_binary_loc) [(X ^ Y) & Y]: Remove and merge
with...
* match.pd ((X & Y) ^ Y): ... this.
((X & Y) & Y, (X | Y) | Y, (X ^ Y) ^ Y, (X & Y) & (X & Z), (X | Y)
| (X | Z), (X ^ Y) ^ (X ^ Z)): New transformations.
gcc/testsuite/
* gcc.dg/tree-ssa/bit-assoc.c: New testcase.
* gcc.dg/tree-ssa/pr69270.c: Adjust.
* gcc.dg/tree-ssa/vrp59.c: Disable forwprop.
Here it is again, I just replaced convert with convert[12] in the last 2
transforms. This should matter for (unsigned)(si & 42) & (ui & 42u). I
didn't change it in the other transform, because it would only matter in
the case (T)(X & CST) & CST, which I think would be better served by
extending the transform that currently handles (X & CST1) & CST2 (not done
in this patch).
--
Marc Glisse
Index: gcc/fold-const.c
===================================================================
--- gcc/fold-const.c (revision 236047)
+++ gcc/fold-const.c (working copy)
@@ -10064,59 +10064,20 @@ fold_binary_loc (location_t loc,
}
/* Fold !X & 1 as X == 0. */
if (TREE_CODE (arg0) == TRUTH_NOT_EXPR
&& integer_onep (arg1))
{
tem = TREE_OPERAND (arg0, 0);
return fold_build2_loc (loc, EQ_EXPR, type, tem,
build_zero_cst (TREE_TYPE (tem)));
}
- /* Fold (X ^ Y) & Y as ~X & Y. */
- if (TREE_CODE (arg0) == BIT_XOR_EXPR
- && operand_equal_p (TREE_OPERAND (arg0, 1), arg1, 0))
- {
- tem = fold_convert_loc (loc, type, TREE_OPERAND (arg0, 0));
- return fold_build2_loc (loc, BIT_AND_EXPR, type,
- fold_build1_loc (loc, BIT_NOT_EXPR, type, tem),
- fold_convert_loc (loc, type, arg1));
- }
- /* Fold (X ^ Y) & X as ~Y & X. */
- if (TREE_CODE (arg0) == BIT_XOR_EXPR
- && operand_equal_p (TREE_OPERAND (arg0, 0), arg1, 0)
- && reorder_operands_p (TREE_OPERAND (arg0, 1), arg1))
- {
- tem = fold_convert_loc (loc, type, TREE_OPERAND (arg0, 1));
- return fold_build2_loc (loc, BIT_AND_EXPR, type,
- fold_build1_loc (loc, BIT_NOT_EXPR, type, tem),
- fold_convert_loc (loc, type, arg1));
- }
- /* Fold X & (X ^ Y) as X & ~Y. */
- if (TREE_CODE (arg1) == BIT_XOR_EXPR
- && operand_equal_p (arg0, TREE_OPERAND (arg1, 0), 0))
- {
- tem = fold_convert_loc (loc, type, TREE_OPERAND (arg1, 1));
- return fold_build2_loc (loc, BIT_AND_EXPR, type,
- fold_convert_loc (loc, type, arg0),
- fold_build1_loc (loc, BIT_NOT_EXPR, type, tem));
- }
- /* Fold X & (Y ^ X) as ~Y & X. */
- if (TREE_CODE (arg1) == BIT_XOR_EXPR
- && operand_equal_p (arg0, TREE_OPERAND (arg1, 1), 0)
- && reorder_operands_p (arg0, TREE_OPERAND (arg1, 0)))
- {
- tem = fold_convert_loc (loc, type, TREE_OPERAND (arg1, 0));
- return fold_build2_loc (loc, BIT_AND_EXPR, type,
- fold_build1_loc (loc, BIT_NOT_EXPR, type, tem),
- fold_convert_loc (loc, type, arg0));
- }
-
/* Fold (X * Y) & -(1 << CST) to X * Y if Y is a constant
multiple of 1 << CST. */
if (TREE_CODE (arg1) == INTEGER_CST)
{
wide_int cst1 = arg1;
wide_int ncst1 = -cst1;
if ((cst1 & ncst1) == ncst1
&& multiple_of_p (type, arg0,
wide_int_to_tree (TREE_TYPE (arg1), ncst1)))
return fold_convert_loc (loc, type, arg0);
Index: gcc/match.pd
===================================================================
--- gcc/match.pd (revision 236047)
+++ gcc/match.pd (working copy)
@@ -667,39 +667,70 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
(if (tree_nop_conversion_p (type, TREE_TYPE (@0))
&& tree_nop_conversion_p (type, TREE_TYPE (@1)))
(bit_xor (convert @0) (convert @1))))
/* Convert ~X ^ C to X ^ ~C. */
(simplify
(bit_xor (convert? (bit_not @0)) INTEGER_CST@1)
(if (tree_nop_conversion_p (type, TREE_TYPE (@0)))
(bit_xor (convert @0) (bit_not @1))))
-/* Fold (X & Y) ^ Y as ~X & Y. */
-(simplify
- (bit_xor:c (bit_and:c @0 @1) @1)
- (bit_and (bit_not @0) @1))
+/* Fold (X & Y) ^ Y and (X ^ Y) & Y as ~X & Y. */
+(for opo (bit_and bit_xor)
+ opi (bit_xor bit_and)
+ (simplify
+ (opo:c (opi:c @0 @1) @1)
+ (bit_and (bit_not @0) @1)))
/* Given a bit-wise operation CODE applied to ARG0 and ARG1, see if both
operands are another bit-wise operation with a common input. If so,
distribute the bit operations to save an operation and possibly two if
constants are involved. For example, convert
(A | B) & (A | C) into A | (B & C)
Further simplification will occur if B and C are constants. */
(for op (bit_and bit_ior bit_xor)
rop (bit_ior bit_and bit_and)
(simplify
(op (convert? (rop:c @0 @1)) (convert? (rop:c @0 @2)))
(if (tree_nop_conversion_p (type, TREE_TYPE (@1))
&& tree_nop_conversion_p (type, TREE_TYPE (@2)))
(rop (convert @0) (op (convert @1) (convert @2))))))
+/* Some simple reassociation for bit operations, also handled in reassoc. */
+/* (X & Y) & Y -> X & Y
+ (X | Y) | Y -> X | Y */
+(for op (bit_and bit_ior)
+ (simplify
+ (op:c (convert?@2 (op:c @0 @1)) (convert? @1))
+ @2))
+/* (X ^ Y) ^ Y -> X */
+(simplify
+ (bit_xor:c (convert? (bit_xor:c @0 @1)) (convert? @1))
+ (if (tree_nop_conversion_p (type, TREE_TYPE (@0)))
+ (convert @0)))
+/* (X & Y) & (X & Z) -> (X & Y) & Z
+ (X | Y) | (X | Z) -> (X | Y) | Z */
+(for op (bit_and bit_ior)
+ (simplify
+ (op:c (convert1?@3 (op:c@4 @0 @1)) (convert2?@5 (op:c@6 @0 @2)))
+ (if (tree_nop_conversion_p (type, TREE_TYPE (@1))
+ && tree_nop_conversion_p (type, TREE_TYPE (@2)))
+ (if (single_use (@5) && single_use (@6))
+ (op @3 (convert @2))
+ (if (single_use (@3) && single_use (@4))
+ (op (convert @1) @5))))))
+/* (X ^ Y) ^ (X ^ Z) -> Y ^ Z */
+(simplify
+ (bit_xor (convert1? (bit_xor:c @0 @1)) (convert2? (bit_xor:c @0 @2)))
+ (if (tree_nop_conversion_p (type, TREE_TYPE (@1))
+ && tree_nop_conversion_p (type, TREE_TYPE (@2)))
+ (convert (bit_xor @1 @2))))
(simplify
(abs (abs@1 @0))
@1)
(simplify
(abs (negate @0))
(abs @0))
(simplify
(abs tree_expr_nonnegative_p@0)
@0)
Index: gcc/testsuite/gcc.dg/tree-ssa/bit-assoc.c
===================================================================
--- gcc/testsuite/gcc.dg/tree-ssa/bit-assoc.c (revision 0)
+++ gcc/testsuite/gcc.dg/tree-ssa/bit-assoc.c (working copy)
@@ -0,0 +1,29 @@
+/* { dg-do compile } */
+/* { dg-options "-O -fdump-tree-forwprop1-details -fdump-tree-ccp1-details" }
*/
+
+int f1(int a, int b){
+ int c = a & b;
+ return c & b;
+}
+int f2(int a, int b){
+ int c = a | b;
+ return b | c;
+}
+int g1(int a, int b, int c){
+ int d = a & b;
+ int e = b & c;
+ return d & e;
+}
+int g2(int a, int b, int c){
+ int d = a | b;
+ int e = c | b;
+ return d | e;
+}
+int g3(int a, int b, int c){
+ int d = a ^ b;
+ int e = b ^ c;
+ return e ^ d;
+}
+
+/* { dg-final { scan-tree-dump-times "Match-and-simplified" 2 "ccp1" } } */
+/* { dg-final { scan-tree-dump-times "gimple_simplified" 3 "forwprop1" } } */
Index: gcc/testsuite/gcc.dg/tree-ssa/pr69270.c
===================================================================
--- gcc/testsuite/gcc.dg/tree-ssa/pr69270.c (revision 236047)
+++ gcc/testsuite/gcc.dg/tree-ssa/pr69270.c (working copy)
@@ -1,21 +1,23 @@
/* { dg-do compile } */
/* { dg-options "-O2 -fsplit-paths -fdump-tree-dom3-details" } */
/* There should be two references to bufferstep that turn into
constants. */
/* { dg-final { scan-tree-dump-times "Replaced .bufferstep_\[0-9\]+. with
constant .0." 1 "dom3"} } */
/* { dg-final { scan-tree-dump-times "Replaced .bufferstep_\[0-9\]+. with
constant .1." 1 "dom3"} } */
/* And some assignments ought to fold down to constants. */
-/* { dg-final { scan-tree-dump-times "Folded to: _\[0-9\]+ = 1;" 2 "dom3"} } */
-/* { dg-final { scan-tree-dump-times "Folded to: _\[0-9\]+ = 0;" 2 "dom3"} } */
+/* { dg-final { scan-tree-dump-times "Folded to: _\[0-9\]+ = -1;" 1 "dom3"} }
*/
+/* { dg-final { scan-tree-dump-times "Folded to: _\[0-9\]+ = -2;" 1 "dom3"} }
*/
+/* { dg-final { scan-tree-dump-times "Folded to: _\[0-9\]+ = 1;" 1 "dom3"} } */
+/* { dg-final { scan-tree-dump-times "Folded to: _\[0-9\]+ = 0;" 1 "dom3"} } */
/* The XOR operations should have been optimized to constants. */
/* { dg-final { scan-tree-dump-not "bit_xor" "dom3"} } */
extern int *stepsizeTable;
void
adpcm_coder (signed char *outdata, int len)
{
Index: gcc/testsuite/gcc.dg/tree-ssa/vrp59.c
===================================================================
--- gcc/testsuite/gcc.dg/tree-ssa/vrp59.c (revision 236047)
+++ gcc/testsuite/gcc.dg/tree-ssa/vrp59.c (working copy)
@@ -1,12 +1,12 @@
/* { dg-do compile } */
-/* { dg-options "-O2 -fno-tree-ccp -fdump-tree-vrp1" } */
+/* { dg-options "-O2 -fno-tree-ccp -fno-tree-forwprop -fdump-tree-vrp1" } */
int f(int x)
{
if (x >= 0 && x <= 3)
{
x = x ^ 3;
x = x & 3;
}
return x;
}
