[PATCH] D44367: [InstCombine] peek through FP casts for sign-bit compares (PR36682)

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri added a comment.

Ok, i have limited the test generator to just the `sitofp`, `slt 0` / `sle -1` / `sgt -1` / `sge 0`, added `undef` in the middle of vector variant.
Good news is that all the scalar cases are indeed handled.
Bad news is that half of the vector cases is not handled.
F5886573: cast-int-icmp-eq-0.ll <https://reviews.llvm.org/F5886573> <- just all the vector cases, with your patch.

  $ grep "CHECK-NEXT" cast-int-icmp-eq-0.ll | grep icmp | wc -l
  36
  $ grep "CHECK-NEXT" cast-int-icmp-eq-0.ll | grep bitcast | wc -l
  18 # (so exactly half)
  $ grep "CHECK-NEXT" cast-int-icmp-eq-0.ll | grep -B 1 -A 1 bitcast
  ; CHECK-NEXT:    [[F:%.*]] = sitofp <3 x i32> [[I:%.*]] to <3 x float>
  ; CHECK-NEXT:    [[B:%.*]] = bitcast <3 x float> [[F]] to <3 x i32>
  ; CHECK-NEXT:    [[CMP:%.*]] = icmp slt <3 x i32> [[B]], <i32 0, i32 undef, i32 0>
  --
  ; CHECK-NEXT:    [[F:%.*]] = sitofp <3 x i32> [[I:%.*]] to <3 x float>
  ; CHECK-NEXT:    [[B:%.*]] = bitcast <3 x float> [[F]] to <3 x i32>
  ; CHECK-NEXT:    [[CMP:%.*]] = icmp slt <3 x i32> [[B]], <i32 0, i32 undef, i32 0>
  --
  ; CHECK-NEXT:    [[F:%.*]] = sitofp <3 x i32> [[I:%.*]] to <3 x double>
  ; CHECK-NEXT:    [[B:%.*]] = bitcast <3 x double> [[F]] to <3 x i64>
  ; CHECK-NEXT:    [[CMP:%.*]] = icmp slt <3 x i64> [[B]], <i64 0, i64 undef, i64 0>
  --
  ; CHECK-NEXT:    [[F:%.*]] = sitofp <3 x i32> [[I:%.*]] to <3 x double>
  ; CHECK-NEXT:    [[B:%.*]] = bitcast <3 x double> [[F]] to <3 x i64>
  ; CHECK-NEXT:    [[CMP:%.*]] = icmp slt <3 x i64> [[B]], <i64 0, i64 undef, i64 0>
  --
  ; CHECK-NEXT:    [[F:%.*]] = sitofp <3 x i32> [[I:%.*]] to <3 x half>
  ; CHECK-NEXT:    [[B:%.*]] = bitcast <3 x half> [[F]] to <3 x i16>
  ; CHECK-NEXT:    [[CMP:%.*]] = icmp slt <3 x i16> [[B]], <i16 0, i16 undef, i16 0>
  --
  ; CHECK-NEXT:    [[F:%.*]] = sitofp <3 x i32> [[I:%.*]] to <3 x half>
  ; CHECK-NEXT:    [[B:%.*]] = bitcast <3 x half> [[F]] to <3 x i16>
  ; CHECK-NEXT:    [[CMP:%.*]] = icmp slt <3 x i16> [[B]], <i16 0, i16 undef, i16 0>
  --
  ; CHECK-NEXT:    [[F:%.*]] = sitofp <3 x i64> [[I:%.*]] to <3 x float>
  ; CHECK-NEXT:    [[B:%.*]] = bitcast <3 x float> [[F]] to <3 x i32>
  ; CHECK-NEXT:    [[CMP:%.*]] = icmp slt <3 x i32> [[B]], <i32 0, i32 undef, i32 0>
  --
  ; CHECK-NEXT:    [[F:%.*]] = sitofp <3 x i64> [[I:%.*]] to <3 x float>
  ; CHECK-NEXT:    [[B:%.*]] = bitcast <3 x float> [[F]] to <3 x i32>
  ; CHECK-NEXT:    [[CMP:%.*]] = icmp slt <3 x i32> [[B]], <i32 0, i32 undef, i32 0>
  --
  ; CHECK-NEXT:    [[F:%.*]] = sitofp <3 x i64> [[I:%.*]] to <3 x double>
  ; CHECK-NEXT:    [[B:%.*]] = bitcast <3 x double> [[F]] to <3 x i64>
  ; CHECK-NEXT:    [[CMP:%.*]] = icmp slt <3 x i64> [[B]], <i64 0, i64 undef, i64 0>
  --
  ; CHECK-NEXT:    [[F:%.*]] = sitofp <3 x i64> [[I:%.*]] to <3 x double>
  ; CHECK-NEXT:    [[B:%.*]] = bitcast <3 x double> [[F]] to <3 x i64>
  ; CHECK-NEXT:    [[CMP:%.*]] = icmp slt <3 x i64> [[B]], <i64 0, i64 undef, i64 0>
  --
  ; CHECK-NEXT:    [[F:%.*]] = sitofp <3 x i64> [[I:%.*]] to <3 x half>
  ; CHECK-NEXT:    [[B:%.*]] = bitcast <3 x half> [[F]] to <3 x i16>
  ; CHECK-NEXT:    [[CMP:%.*]] = icmp slt <3 x i16> [[B]], <i16 0, i16 undef, i16 0>
  --
  ; CHECK-NEXT:    [[F:%.*]] = sitofp <3 x i64> [[I:%.*]] to <3 x half>
  ; CHECK-NEXT:    [[B:%.*]] = bitcast <3 x half> [[F]] to <3 x i16>
  ; CHECK-NEXT:    [[CMP:%.*]] = icmp slt <3 x i16> [[B]], <i16 0, i16 undef, i16 0>
  --
  ; CHECK-NEXT:    [[F:%.*]] = sitofp <3 x i16> [[I:%.*]] to <3 x float>
  ; CHECK-NEXT:    [[B:%.*]] = bitcast <3 x float> [[F]] to <3 x i32>
  ; CHECK-NEXT:    [[CMP:%.*]] = icmp slt <3 x i32> [[B]], <i32 0, i32 undef, i32 0>
  --
  ; CHECK-NEXT:    [[F:%.*]] = sitofp <3 x i16> [[I:%.*]] to <3 x float>
  ; CHECK-NEXT:    [[B:%.*]] = bitcast <3 x float> [[F]] to <3 x i32>
  ; CHECK-NEXT:    [[CMP:%.*]] = icmp slt <3 x i32> [[B]], <i32 0, i32 undef, i32 0>
  --
  ; CHECK-NEXT:    [[F:%.*]] = sitofp <3 x i16> [[I:%.*]] to <3 x double>
  ; CHECK-NEXT:    [[B:%.*]] = bitcast <3 x double> [[F]] to <3 x i64>
  ; CHECK-NEXT:    [[CMP:%.*]] = icmp slt <3 x i64> [[B]], <i64 0, i64 undef, i64 0>
  --
  ; CHECK-NEXT:    [[F:%.*]] = sitofp <3 x i16> [[I:%.*]] to <3 x double>
  ; CHECK-NEXT:    [[B:%.*]] = bitcast <3 x double> [[F]] to <3 x i64>
  ; CHECK-NEXT:    [[CMP:%.*]] = icmp slt <3 x i64> [[B]], <i64 0, i64 undef, i64 0>
  --
  ; CHECK-NEXT:    [[F:%.*]] = sitofp <3 x i16> [[I:%.*]] to <3 x half>
  ; CHECK-NEXT:    [[B:%.*]] = bitcast <3 x half> [[F]] to <3 x i16>
  ; CHECK-NEXT:    [[CMP:%.*]] = icmp slt <3 x i16> [[B]], <i16 0, i16 undef, i16 0>
  --
  ; CHECK-NEXT:    [[F:%.*]] = sitofp <3 x i16> [[I:%.*]] to <3 x half>
  ; CHECK-NEXT:    [[B:%.*]] = bitcast <3 x half> [[F]] to <3 x i16>
  ; CHECK-NEXT:    [[CMP:%.*]] = icmp slt <3 x i16> [[B]], <i16 0, i16 undef, i16 0>

Unless it is because i'm using yesterday's trunk, I think the test coverage needs improving.
I think i should go ahead and commit that initial testfile now, unless it is too large?


https://reviews.llvm.org/D44367