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| author | Paolo Bonzini <bonzini@gnu.org> | 2008-03-12 15:33:45 +0000 |
|---|---|---|
| committer | Paolo Bonzini <bonzini@gcc.gnu.org> | 2008-03-12 15:33:45 +0000 |
| commit | c83bd37c9d8859d4e8dc6d1f021c6e8b8ffabb99 (patch) | |
| tree | c1959cceb74dfe8a50fb7fa66a39bd956922bdbb /gcc/fold-const.c | |
| parent | 70fef63aef8a841f20cfa08c88da9ca871a3c8f3 (diff) | |
| download | gcc-c83bd37c9d8859d4e8dc6d1f021c6e8b8ffabb99.zip gcc-c83bd37c9d8859d4e8dc6d1f021c6e8b8ffabb99.tar.gz gcc-c83bd37c9d8859d4e8dc6d1f021c6e8b8ffabb99.tar.bz2 | |
re PR rtl-optimization/34522 (inefficient code for long long multiply when only low bits are needed)
2008-03-12 Paolo Bonzini <bonzini@gnu.org>
PR tree-opt/35422
* fold-const.c (fold_unary) <NOP_EXPR>: Distribute a narrowing
conversion to the operands of a multiplication.
testsuite:
2008-03-12 Paolo Bonzini <bonzini@gnu.org>
PR tree-opt/35422
* gcc.dg/vect/slp-7.c: Change target keywords required for vectorizing
third loop.
* gcc.target/i386/pr35422.c: New.
From-SVN: r133144
Diffstat (limited to 'gcc/fold-const.c')
| -rw-r--r-- | gcc/fold-const.c | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/gcc/fold-const.c b/gcc/fold-const.c index 4774661..7cf132b 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -7926,6 +7926,26 @@ fold_unary (enum tree_code code, tree type, tree op0) return fold_build1 (BIT_NOT_EXPR, type, fold_convert (type, tem)); } + /* Convert (T1)(X * Y) into (T1)X * (T1)Y if T1 is narrower than the + type of X and Y (integer types only). */ + if (INTEGRAL_TYPE_P (type) + && TREE_CODE (op0) == MULT_EXPR + && INTEGRAL_TYPE_P (TREE_TYPE (op0)) + && TYPE_PRECISION (type) < TYPE_PRECISION (TREE_TYPE (op0))) + { + /* Be careful not to introduce new overflows. */ + tree mult_type; + if (TYPE_OVERFLOW_WRAPS (type)) + mult_type = type; + else + mult_type = unsigned_type_for (type); + + tem = fold_build2 (MULT_EXPR, mult_type, + fold_convert (mult_type, TREE_OPERAND (op0, 0)), + fold_convert (mult_type, TREE_OPERAND (op0, 1))); + return fold_convert (type, tem); + } + tem = fold_convert_const (code, type, op0); return tem ? tem : NULL_TREE; |