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x64: port select to ISLE (#3682)

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* x64: port `select` using an FP comparison to ISLE

This change includes quite a few interlocking parts, required mainly by
the current x64 conventions in ISLE:
 - it adds a way to emit a `cmove` with multiple OR-ing conditions;
   because x64 ISLE cannot currently safely emit a comparison followed
   by several jumps, this adds `MachInst::CmoveOr` and
   `MachInst::XmmCmoveOr` macro instructions. Unfortunately, these macro
   instructions hide the multi-instruction sequence in `lower.isle`
 - to properly keep track of what instructions consume and produce
   flags, @cfallin added a way to pass around variants of
   `ConsumesFlags` and `ProducesFlags`--these changes affect all
   backends
 - then, to lower the `fcmp + select` CLIF, this change adds several
   `cmove*_from_values` helpers that perform all of the awkward
   conversions between `Value`, `ValueReg`, `Reg`, and `Gpr/Xmm`; one
   upside is that now these lowerings have much-improved documentation
   explaining why the various `FloatCC` and `CC` choices are made the
   the way they are.

Co-authored-by: Chris Fallin <chris@cfallin.org>
This commit is contained in:
Andrew Brown
2022-02-23 10:03:16 -08:00
committed by GitHub
parent 5a5e401a9c
commit f87c61176a
20 changed files with 3163 additions and 2272 deletions
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18
cranelift/filetests/filetests/isa/x64/cmp-mem-bug.clif
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@@ -43,7 +43,7 @@ block0(v0: f64, v1: i64):
; Entry block: 0
; Block 0:
; (original IR block: block0)
; (instruction range: 0 .. 17)
; (instruction range: 0 .. 16)
; Inst 0: pushq %rbp
; Inst 1: movq %rsp, %rbp
; Inst 2: movsd 0(%rdi), %xmm1
@@ -52,14 +52,12 @@ block0(v0: f64, v1: i64):
; Inst 5: setz %sil
; Inst 6: andl %edi, %esi
; Inst 7: andq $1, %rsi
; Inst 8: ucomisd %xmm1, %xmm0
; Inst 8: ucomisd %xmm0, %xmm1
; Inst 9: movaps %xmm0, %xmm1
; Inst 10: jnp $next; movsd %xmm0, %xmm1; $next:
; Inst 11: jz $next; movsd %xmm0, %xmm1; $next:
; Inst 12: movq %rsi, %rax
; Inst 13: movaps %xmm1, %xmm0
; Inst 14: movq %rbp, %rsp
; Inst 15: popq %rbp
; Inst 16: ret
; Inst 10: jz $check; movsd %xmm0, %xmm1; $check: jnp $next; movsd %xmm0, %xmm1; $next
; Inst 11: movq %rsi, %rax
; Inst 12: movaps %xmm1, %xmm0
; Inst 13: movq %rbp, %rsp
; Inst 14: popq %rbp
; Inst 15: ret
; }}