sparse/sparse-dev.git - Sparse's development tree with unstable git history

Age	Commit message (Collapse)	Author	Files	Lines
2018-08-22	simplify ((x & M) >> S) when (M >> S) == (-1 >> S)	Luc Van Oostenryck	1	-1/+0
	The instructions LSR(AND(x, M), S) are already simplified into AND(LSR(x, S), (M >> S)) but only if AND(x, M) has a single user. However, if (M >> S) == (-1 >> S), the AND part is redundant and the whole can always directly be simplified into LSR(x, S). For example, code like: unsigned foo(unsigned x) { unsigned t = (x & 0xfffff000); return ((t >> 12) ^ (x >> 12)) & t; } is now optimized into: foo: ret.32 $0 because (t >> 12) is simplified into (x >> 12). Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
2018-08-22	add testcases for {LSR,SHL}(AND(x, M), S) with shared AND(x, M)	Luc Van Oostenryck	1	-0/+19
	The pattern LSR(AND(x, M), S) is already generically simplified into ((x >> S) & (M >> S)) but only if the sub-expression AND(x, M) is not shared with some other expressions because the simplification modify it. But for some special cases the expression can be simplified even if the sub-expression is shared because the simplification doesn't need to modify this AND(x, M) part. Add the testcases for LSR and the incoming SHL. Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>