Constant fold {-1,-1} << 1 in simplify-rtx.cc

This patch addresses a missed optimization opportunity in the RTL
optimization passes.  The function simplify_const_binary_operation
will constant fold binary operators with two CONST_INT operands,
and those with two CONST_VECTOR operands, but is missing compile-time
evaluation of binary operators with a CONST_VECTOR and a CONST_INT,
such as vector shifts and rotates.

The first version of this patch didn't contain a switch statement to
explicitly check for valid binary opcodes, which bootstrapped and
regression tested fine, but my paranoia has got the better of me,
so this version now checks that VEC_SELECT or some funky (future)
rtx_code doesn't cause problems.

2024-05-09  Roger Sayle  <roger@nextmovesoftware.com>

gcc/ChangeLog
	* simplify-rtx.cc (simplify_const_binary_operation): Constant
	fold binary operations where the LHS is CONST_VECTOR and the
	RHS is CONST_INT (or CONST_DOUBLE) such as vector shifts.

0 files changed, 0 insertions, 0 deletions