diff options
| -rw-r--r-- | mem.c | 37 | ||||
| -rw-r--r-- | test/mem2.ssa | 32 |
2 files changed, 64 insertions, 5 deletions
diff --git a/mem.c b/mem.c index 1db632f..8bde4be 100644 --- a/mem.c +++ b/mem.c @@ -1,6 +1,7 @@ #include "all.h" typedef struct Range Range; +typedef struct Store Store; typedef struct Slot Slot; /* require use, maintains use counts */ @@ -95,6 +96,11 @@ struct Range { int a, b; }; +struct Store { + int ip; + Ins *i; +}; + struct Slot { int t; int sz; @@ -102,6 +108,8 @@ struct Slot { bits l; Range r; Slot *s; + Store *dead; + int ndead; }; static inline int @@ -159,15 +167,20 @@ load(Ref r, bits x, int ip, Fn *fn, Slot *sl) } static void -store(Ref r, bits x, int ip, Fn *fn, Slot *sl) +store(Ref r, bits x, int ip, Ins *i, Fn *fn, Slot *sl) { int64_t off; Slot *s; if (slot(&s, &off, r, fn, sl)) { - if (s->l) + if (s->l) { radd(&s->r, ip); - s->l &= ~(x << off); + s->l &= ~(x << off); + } else { + vgrow(&s->dead, ++s->ndead); + s->dead[s->ndead-1].ip = ip; + s->dead[s->ndead-1].i = i; + } } } @@ -223,6 +236,8 @@ coalesce(Fn *fn) s->sz = t->alias.u.loc.sz; s->m = t->alias.u.loc.m; s->s = 0; + s->dead = vnew(0, sizeof s->dead[0], PHeap); + s->ndead = 0; } } @@ -264,14 +279,14 @@ coalesce(Fn *fn) } if (isstore(i->op)) { x = BIT(storesz(i)) - 1; - store(arg[1], x, ip--, fn, sl); + store(arg[1], x, ip--, i, fn, sl); } if (i->op == Oblit0) { assert((i+1)->op == Oblit1); assert(rtype((i+1)->arg[0]) == RInt); sz = abs(rsval((i+1)->arg[0])); x = sz >= NBit ? (bits)-1 : BIT(sz) - 1; - store(arg[1], x, ip--, fn, sl); + store(arg[1], x, ip--, i, fn, sl); load(arg[0], x, ip, fn, sl); vgrow(&bl, ++nbl); bl[nbl-1] = i; @@ -289,6 +304,16 @@ coalesce(Fn *fn) } free(br); + /* kill dead stores */ + for (s=sl; s<&sl[nsl]; s++) + for (n=0; n<s->ndead; n++) + if (!rin(s->r, s->dead[n].ip)) { + i = s->dead[n].i; + if (i->op == Oblit0) + *(i+1) = (Ins){.op = Onop}; + *i = (Ins){.op = Onop}; + } + /* kill slots with an empty live range */ total = 0; freed = 0; @@ -446,5 +471,7 @@ coalesce(Fn *fn) printfn(fn, stderr); } + for (s=sl; s<&sl[nsl]; s++) + vfree(s->dead); vfree(sl); } diff --git a/test/mem2.ssa b/test/mem2.ssa new file mode 100644 index 0000000..4a136b4 --- /dev/null +++ b/test/mem2.ssa @@ -0,0 +1,32 @@ +# Ember Sawady reported this bug +# in stack-slot coalescing + +type :t = { w 2 } + +function :t $func() { +@start.0 + %temp =l alloc4 4 + %ret =l alloc4 8 + storew 1, %temp + # storew can also go here + %field =l add %ret, 4 + storew 2, %ret + blit %temp, %field, 4 + # removing either of these storews causes it to work + storew 2, %ret + ret %ret +} + +export function w $main() { +@start + %ret =:t call $func() + %fptr =l add %ret, 4 + %field =w loaduw %fptr + %x =w ceqw %field, 1 + jnz %x, @passed, @failed +@failed + # this fails despite 1 => temp => ret + 4 => field + call $abort() +@passed + ret 0 +} |