f40d602170
Issue #100 demonstrated that register allocation for aliased registers is fundamentally broken. The root of the issue is that currently accesses to the same virtual register with different masks are treated as different registers. This PR takes a different approach: * Liveness analysis is masked: we now properly consider which parts of a register are live * Register allocation produces a mapping from virtual to physical ID, and aliasing is applied later In addition, a new pass ZeroExtend32BitOutputs accounts for the fact that 32-bit writes in 64-bit mode should actually be treated as 64-bit writes (the result is zero-extended). Closes #100
55 lines
2.0 KiB
Go
55 lines
2.0 KiB
Go
package reg
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// Collection represents a collection of virtual registers. This is primarily
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// useful for allocating virtual registers with distinct IDs.
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type Collection struct {
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idx map[Kind]Index
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}
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// NewCollection builds an empty register collection.
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func NewCollection() *Collection {
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return &Collection{
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idx: map[Kind]Index{},
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}
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}
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// VirtualRegister allocates and returns a new virtual register of the given kind and width.
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func (c *Collection) VirtualRegister(k Kind, s Spec) Virtual {
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idx := c.idx[k]
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c.idx[k]++
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return NewVirtual(idx, k, s)
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}
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// GP8L allocates and returns a general-purpose 8-bit register (low byte).
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func (c *Collection) GP8L() GPVirtual { return c.GP(S8L) }
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// GP8H allocates and returns a general-purpose 8-bit register (high byte).
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func (c *Collection) GP8H() GPVirtual { return c.GP(S8H) }
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// GP8 allocates and returns a general-purpose 8-bit register (low byte).
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func (c *Collection) GP8() GPVirtual { return c.GP8L() }
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// GP16 allocates and returns a general-purpose 16-bit register.
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func (c *Collection) GP16() GPVirtual { return c.GP(S16) }
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// GP32 allocates and returns a general-purpose 32-bit register.
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func (c *Collection) GP32() GPVirtual { return c.GP(S32) }
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// GP64 allocates and returns a general-purpose 64-bit register.
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func (c *Collection) GP64() GPVirtual { return c.GP(S64) }
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// GP allocates and returns a general-purpose register of the given width.
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func (c *Collection) GP(s Spec) GPVirtual { return newgpv(c.VirtualRegister(KindGP, s)) }
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// XMM allocates and returns a 128-bit vector register.
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func (c *Collection) XMM() VecVirtual { return c.Vec(S128) }
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// YMM allocates and returns a 256-bit vector register.
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func (c *Collection) YMM() VecVirtual { return c.Vec(S256) }
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// ZMM allocates and returns a 512-bit vector register.
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func (c *Collection) ZMM() VecVirtual { return c.Vec(S512) }
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// Vec allocates and returns a vector register of the given width.
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func (c *Collection) Vec(s Spec) VecVirtual { return newvecv(c.VirtualRegister(KindVector, s)) }
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