Bootstrapped and tested on x86_64-unknown-linux-gnu.
Richard.
2016-04-28 Richard Biener <rguent...@suse.de>
PR tree-optimization/70840
* match.pd: powi(-x, y) and powi(|x|,y) -> powi(x,y) if y is even;
Fix pow(copysign(x, y), z) -> pow(x, z) and add powi variant;
Mark x * pow(x,c) -> pow(x,c+1) commutative.
Add powi(x,y) * powi(z,y) -> powi(x*z,y).
Index: gcc/match.pd
===================================================================
--- gcc/match.pd (revision 235544)
+++ gcc/match.pd (working copy)
@@ -366,6 +366,12 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
(with { HOST_WIDE_INT n; }
(if (real_isinteger (&TREE_REAL_CST (@1), &n) && (n & 1) == 0)
(pows @0 @1)))))
+ /* Likewise for powi. */
+ (for pows (POWI)
+ (simplify
+ (pows (op @0) INTEGER_CST@1)
+ (if (wi::bit_and (@1, 1) == 0)
+ (pows @0 @1))))
/* Strip negate and abs from both operands of hypot. */
(for hypots (HYPOT)
(simplify
@@ -396,10 +402,17 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
(for pows (POW)
copysigns (COPYSIGN)
(simplify
- (pows (copysigns @0 @1) REAL_CST@1)
+ (pows (copysigns @0 @2) REAL_CST@1)
(with { HOST_WIDE_INT n; }
(if (real_isinteger (&TREE_REAL_CST (@1), &n) && (n & 1) == 0)
(pows @0 @1)))))
+/* Likewise for powi. */
+(for pows (POWI)
+ copysigns (COPYSIGN)
+ (simplify
+ (pows (copysigns @0 @2) INTEGER_CST@1)
+ (if (wi::bit_and (@1, 1) == 0)
+ (pows @0 @1))))
(for hypots (HYPOT)
copysigns (COPYSIGN)
@@ -2781,7 +2794,7 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
/* Simplify x * pow(x,c) -> pow(x,c+1). */
(simplify
- (mult @0 (POW:s @0 REAL_CST@1))
+ (mult:c @0 (POW:s @0 REAL_CST@1))
(if (!TREE_OVERFLOW (@1))
(POW @0 (plus @1 { build_one_cst (type); }))))
@@ -2819,6 +2832,11 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
(mult (POW:s @0 @1) (POW:s @2 @1))
(POW (mult @0 @2) @1))
+ /* Simplify powi(x,y) * powi(z,y) -> powi(x*z,y). */
+ (simplify
+ (mult (POWI:s @0 @1) (POWI:s @2 @1))
+ (POWI (mult @0 @2) @1))
+
/* Simplify pow(x,c) / x -> pow(x,c-1). */
(simplify
(rdiv (POW:s @0 REAL_CST@1) @0)
