[all-commits] [llvm/llvm-project] b09b05: [M68k] Fix incorrect boolean content type (#152572)

[Dan Salvato via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: b09b05a83ef781da8a967702488d10d4e5e6216d
      https://github.com/llvm/llvm-project/commit/b09b05a83ef781da8a967702488d10d4e5e6216d
  Author: Dan Salvato <dansalvato1 at gmail.com>
  Date:   2025-08-12 (Tue, 12 Aug 2025)

  Changed paths:
    M llvm/lib/Target/M68k/M68kISelLowering.cpp
    M llvm/lib/Target/M68k/M68kInstrArithmetic.td
    M llvm/test/CodeGen/M68k/Arith/add.ll
    M llvm/test/CodeGen/M68k/Arith/smul-with-overflow.ll
    M llvm/test/CodeGen/M68k/Atomics/rmw.ll
    M llvm/test/CodeGen/M68k/CodeModel/Large/Atomics/rmw.ll
    M llvm/test/CodeGen/M68k/Control/cmp.ll
    M llvm/test/CodeGen/M68k/Control/non-cmov-switch.ll
    M llvm/test/CodeGen/M68k/Control/setcc.ll

  Log Message:
  -----------
  [M68k] Fix incorrect boolean content type (#152572)

M68k's SETCC instruction (`scc`) distinctly fills the destination byte
with all 1s. If boolean contents are set to `ZeroOrOneBooleanContent`,
LLVM can mistakenly think the destination holds `0x01` instead of `0xff`
and emit broken code as a result. This change corrects the boolean
content type to `ZeroOrNegativeOneBooleanContent`.

For example, this IR:

```llvm
define dso_local signext range(i8 0, 2) i8 @testBool(i32 noundef %a) local_unnamed_addr #0 {
entry:
  %cmp = icmp eq i32 %a, 4660
  %. = zext i1 %cmp to i8
  ret i8 %.
}
```

would previously build as:

```asm
testBool:                               ; @testBool
	cmpi.l	#4660, (4,%sp)
	seq	%d0
	and.l	#255, %d0
	rts
```

Notice the `zext` is erroneously not clearing the low bits, and thus the
register returns with 255 instead of 1. This patch fixes the issue:

```asm
testBool:                               ; @testBool
	cmpi.l	#4660, (4,%sp)
	seq	%d0
	and.l	#1, %d0
	rts
```

Most of the tests containing `scc` suffered from the same value error as
described above, so those tests have been updated to match the new
output (which also logically corrects them).



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