[PATCH] D83523: MachineSink: permit sinking into INLINEASM_BR indirect targets

[James Y Knight via Phabricator via llvm-commits]

jyknight added a comment.

It looks like the issue shown in this test-case appears in Two-Address instruction pass, not Machine Sink.

We go from:

  bb.0 (%ir-block.1):
    successors: %bb.2(0x80000000), %bb.1(0x00000000); %bb.2(100.00%), %bb.1(0.00%)
    liveins: $rdi
    %1:gr64 = COPY killed $rdi
    %0:gr64 = nuw ADD64ri8 %1:gr64(tied-def 0), 24, implicit-def dead $eflags
    INLINEASM_BR &"# $0 $1 $2" [sideeffect] [mayload] [maystore] [attdialect], $0:[mem:m], killed %1:gr64, 1, $noreg, 24, $noreg, $1:[imm], 1, $2:[imm], blockaddress(@klist_dec_and_del, %ir-block.4), $
  3:[clobber], implicit-def dead early-clobber $df, $4:[clobber], implicit-def early-clobber $fpsw, $5:[clobber], implicit-def dead early-clobber $eflags
    JMP_1 %bb.2
  
  bb.1 (%ir-block.4, address-taken):
  ; predecessors: %bb.0
    successors: %bb.2(0x80000000); %bb.2(100.00%)
  
    MOV64mi32 killed %0:gr64, 1, $noreg, -24, $noreg, 0 :: (store 8 into %ir.6)
  
  bb.2 (%ir-block.7):
  ; predecessors: %bb.0, %bb.1
  
    RET 0, undef $eax

then replace the ADD64ri8 with a LEA64r -- but place it _after_ the INLINEASM_BR,

   bb.0 (%ir-block.1):
     successors: %bb.2(0x80000000), %bb.1(0x00000000); %bb.2(100.00%), %bb.1(0.00%)
     liveins: $rdi
     %1:gr64 = COPY killed $rdi
  -  %0:gr64 = nuw ADD64ri8 %1:gr64(tied-def 0), 24, implicit-def dead $eflags
  -  INLINEASM_BR &"# $0 $1 $2" [sideeffect] [mayload] [maystore] [attdialect], $0:[mem:m], killed %1:gr64, 1, $noreg, 24, $noreg, $1:[imm], 1, $2:[imm], blockaddress(@klist_dec_and_del, %ir-block.4), $3:[clobber], implicit-def dead early-clobber $df, $4:[clobber], implicit-def early-clobber $fpsw, $5:[clobber], implicit-def dead early-clobber $eflags
  +  INLINEASM_BR &"# $0 $1 $2" [sideeffect] [mayload] [maystore] [attdialect], $0:[mem:m], %1:gr64, 1, $noreg, 24, $noreg, $1:[imm], 1, $2:[imm], blockaddress(@klist_dec_and_del, %ir-block.4), $3:[clobber], implicit-def dead early-clobber $df, $4:[clobber], implicit-def early-clobber $fpsw, $5:[clobber], implicit-def dead early-clobber $eflags
  +  %0:gr64 = LEA64r killed %1:gr64, 1, $noreg, 24, $noreg
     JMP_1 %bb.2


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https://reviews.llvm.org/D83523