[InstCombine] [NFC] Add tests for peeking through unsigned FP casts for zero-equality compares (PR36682)

Summary:
This pattern came up in PR36682 / D44390
https://bugs.llvm.org/show_bug.cgi?id=36682
https://reviews.llvm.org/D44390
https://godbolt.org/g/oKvT5H

Looking at the IR pattern in question, as per [[ https://github.com/rutgers-apl/alive-nj | alive-nj ]], for all the type combinations i checked
(input: `i16`, `i32`, `i64`; intermediate: `half`/`i16`, `float`/`i32`, `double`/`i64`)
for the following `icmp` comparisons the `uitofp`+`bitcast` can be dropped:
* `eq 0`
* `ne 0`
I did not check vectors, but i'm guessing it's the same there.
{F5889189}

Thus all these cases are in the testcase (along with the vector variant with additional `undef` element in the middle).
There are no negative patterns here (unless alive-nj lied/is broken), all of these should be optimized.

Generated with
{F5889196}

Reviewers: spatel, majnemer, efriedma, arsenm

Reviewed By: spatel

Subscribers: wdng, llvm-commits

Differential Revision: https://reviews.llvm.org/D44416

llvm-svn: 327534

1 files changed, 243 insertions, 0 deletions

diff --git a/llvm/test/Transforms/InstCombine/cast-unsigned-icmp-eqcmp-0.ll b/llvm/test/Transforms/InstCombine/cast-unsigned-icmp-eqcmp-0.ll
new file mode 100644
index 00000000000..f54388377bc
--- /dev/null
+++ b/llvm/test/Transforms/InstCombine/cast-unsigned-icmp-eqcmp-0.ll
@@ -0,0 +1,243 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -instcombine -S | FileCheck %s
+
+; target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+
+; This is related to https://bugs.llvm.org/show_bug.cgi?id=36682
+
+; FIXME: *all* of these are true tests.
+; In *all* of these, uitofp and bitcast should be instcombine'd out.
+
+define i1 @i32_cast_cmp_eq_int_0_uitofp_float(i32 %i) {
+; CHECK-LABEL: @i32_cast_cmp_eq_int_0_uitofp_float(
+; CHECK-NEXT:    [[F:%.*]] = uitofp i32 [[I:%.*]] to float
+; CHECK-NEXT:    [[B:%.*]] = bitcast float [[F]] to i32
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[B]], 0
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %f = uitofp i32 %i to float
+  %b = bitcast float %f to i32
+  %cmp = icmp eq i32 %b, 0
+  ret i1 %cmp
+}
+
+define <2 x i1> @i32_cast_cmp_eq_int_0_uitofp_float_vec(<2 x i32> %i) {
+; CHECK-LABEL: @i32_cast_cmp_eq_int_0_uitofp_float_vec(
+; CHECK-NEXT:    [[F:%.*]] = uitofp <2 x i32> [[I:%.*]] to <2 x float>
+; CHECK-NEXT:    [[B:%.*]] = bitcast <2 x float> [[F]] to <2 x i32>
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq <2 x i32> [[B]], zeroinitializer
+; CHECK-NEXT:    ret <2 x i1> [[CMP]]
+;
+  %f = uitofp <2 x i32> %i to  <2 x float>
+  %b = bitcast <2 x float> %f to <2 x i32>
+  %cmp = icmp eq <2 x i32> %b, <i32 0, i32 0>
+  ret <2 x i1> %cmp
+}
+
+define <3 x i1> @i32_cast_cmp_eq_int_0_uitofp_float_vec_undef(<3 x i32> %i) {
+; CHECK-LABEL: @i32_cast_cmp_eq_int_0_uitofp_float_vec_undef(
+; CHECK-NEXT:    [[F:%.*]] = uitofp <3 x i32> [[I:%.*]] to <3 x float>
+; CHECK-NEXT:    [[B:%.*]] = bitcast <3 x float> [[F]] to <3 x i32>
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq <3 x i32> [[B]], <i32 0, i32 undef, i32 0>
+; CHECK-NEXT:    ret <3 x i1> [[CMP]]
+;
+  %f = uitofp <3 x i32> %i to <3 x float>
+  %b = bitcast <3 x float> %f to <3 x i32>
+  %cmp = icmp eq <3 x i32> %b, <i32 0, i32 undef, i32 0>
+  ret <3 x i1> %cmp
+}
+
+define i1 @i32_cast_cmp_ne_int_0_uitofp_float(i32 %i) {
+; CHECK-LABEL: @i32_cast_cmp_ne_int_0_uitofp_float(
+; CHECK-NEXT:    [[F:%.*]] = uitofp i32 [[I:%.*]] to float
+; CHECK-NEXT:    [[B:%.*]] = bitcast float [[F]] to i32
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i32 [[B]], 0
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %f = uitofp i32 %i to float
+  %b = bitcast float %f to i32
+  %cmp = icmp ne i32 %b, 0
+  ret i1 %cmp
+}
+
+define <2 x i1> @i32_cast_cmp_ne_int_0_uitofp_float_vec(<2 x i32> %i) {
+; CHECK-LABEL: @i32_cast_cmp_ne_int_0_uitofp_float_vec(
+; CHECK-NEXT:    [[F:%.*]] = uitofp <2 x i32> [[I:%.*]] to <2 x float>
+; CHECK-NEXT:    [[B:%.*]] = bitcast <2 x float> [[F]] to <2 x i32>
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne <2 x i32> [[B]], zeroinitializer
+; CHECK-NEXT:    ret <2 x i1> [[CMP]]
+;
+  %f = uitofp <2 x i32> %i to  <2 x float>
+  %b = bitcast <2 x float> %f to <2 x i32>
+  %cmp = icmp ne <2 x i32> %b, <i32 0, i32 0>
+  ret <2 x i1> %cmp
+}
+
+define <3 x i1> @i32_cast_cmp_ne_int_0_uitofp_float_vec_undef(<3 x i32> %i) {
+; CHECK-LABEL: @i32_cast_cmp_ne_int_0_uitofp_float_vec_undef(
+; CHECK-NEXT:    [[F:%.*]] = uitofp <3 x i32> [[I:%.*]] to <3 x float>
+; CHECK-NEXT:    [[B:%.*]] = bitcast <3 x float> [[F]] to <3 x i32>
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne <3 x i32> [[B]], <i32 0, i32 undef, i32 0>
+; CHECK-NEXT:    ret <3 x i1> [[CMP]]
+;
+  %f = uitofp <3 x i32> %i to <3 x float>
+  %b = bitcast <3 x float> %f to <3 x i32>
+  %cmp = icmp ne <3 x i32> %b, <i32 0, i32 undef, i32 0>
+  ret <3 x i1> %cmp
+}
+
+define i1 @i32_cast_cmp_eq_int_0_uitofp_double(i32 %i) {
+; CHECK-LABEL: @i32_cast_cmp_eq_int_0_uitofp_double(
+; CHECK-NEXT:    [[F:%.*]] = uitofp i32 [[I:%.*]] to double
+; CHECK-NEXT:    [[B:%.*]] = bitcast double [[F]] to i64
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i64 [[B]], 0
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %f = uitofp i32 %i to double
+  %b = bitcast double %f to i64
+  %cmp = icmp eq i64 %b, 0
+  ret i1 %cmp
+}
+
+define <2 x i1> @i32_cast_cmp_eq_int_0_uitofp_double_vec(<2 x i32> %i) {
+; CHECK-LABEL: @i32_cast_cmp_eq_int_0_uitofp_double_vec(
+; CHECK-NEXT:    [[F:%.*]] = uitofp <2 x i32> [[I:%.*]] to <2 x double>
+; CHECK-NEXT:    [[B:%.*]] = bitcast <2 x double> [[F]] to <2 x i64>
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq <2 x i64> [[B]], zeroinitializer
+; CHECK-NEXT:    ret <2 x i1> [[CMP]]
+;
+  %f = uitofp <2 x i32> %i to  <2 x double>
+  %b = bitcast <2 x double> %f to <2 x i64>
+  %cmp = icmp eq <2 x i64> %b, <i64 0, i64 0>
+  ret <2 x i1> %cmp
+}
+
+define <3 x i1> @i32_cast_cmp_eq_int_0_uitofp_double_vec_undef(<3 x i32> %i) {
+; CHECK-LABEL: @i32_cast_cmp_eq_int_0_uitofp_double_vec_undef(
+; CHECK-NEXT:    [[F:%.*]] = uitofp <3 x i32> [[I:%.*]] to <3 x double>
+; CHECK-NEXT:    [[B:%.*]] = bitcast <3 x double> [[F]] to <3 x i64>
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq <3 x i64> [[B]], <i64 0, i64 undef, i64 0>
+; CHECK-NEXT:    ret <3 x i1> [[CMP]]
+;
+  %f = uitofp <3 x i32> %i to <3 x double>
+  %b = bitcast <3 x double> %f to <3 x i64>
+  %cmp = icmp eq <3 x i64> %b, <i64 0, i64 undef, i64 0>
+  ret <3 x i1> %cmp
+}
+
+define i1 @i32_cast_cmp_ne_int_0_uitofp_double(i32 %i) {
+; CHECK-LABEL: @i32_cast_cmp_ne_int_0_uitofp_double(
+; CHECK-NEXT:    [[F:%.*]] = uitofp i32 [[I:%.*]] to double
+; CHECK-NEXT:    [[B:%.*]] = bitcast double [[F]] to i64
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i64 [[B]], 0
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %f = uitofp i32 %i to double
+  %b = bitcast double %f to i64
+  %cmp = icmp ne i64 %b, 0
+  ret i1 %cmp
+}
+
+define <2 x i1> @i32_cast_cmp_ne_int_0_uitofp_double_vec(<2 x i32> %i) {
+; CHECK-LABEL: @i32_cast_cmp_ne_int_0_uitofp_double_vec(
+; CHECK-NEXT:    [[F:%.*]] = uitofp <2 x i32> [[I:%.*]] to <2 x double>
+; CHECK-NEXT:    [[B:%.*]] = bitcast <2 x double> [[F]] to <2 x i64>
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne <2 x i64> [[B]], zeroinitializer
+; CHECK-NEXT:    ret <2 x i1> [[CMP]]
+;
+  %f = uitofp <2 x i32> %i to  <2 x double>
+  %b = bitcast <2 x double> %f to <2 x i64>
+  %cmp = icmp ne <2 x i64> %b, <i64 0, i64 0>
+  ret <2 x i1> %cmp
+}
+
+define <3 x i1> @i32_cast_cmp_ne_int_0_uitofp_double_vec_undef(<3 x i32> %i) {
+; CHECK-LABEL: @i32_cast_cmp_ne_int_0_uitofp_double_vec_undef(
+; CHECK-NEXT:    [[F:%.*]] = uitofp <3 x i32> [[I:%.*]] to <3 x double>
+; CHECK-NEXT:    [[B:%.*]] = bitcast <3 x double> [[F]] to <3 x i64>
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne <3 x i64> [[B]], <i64 0, i64 undef, i64 0>
+; CHECK-NEXT:    ret <3 x i1> [[CMP]]
+;
+  %f = uitofp <3 x i32> %i to <3 x double>
+  %b = bitcast <3 x double> %f to <3 x i64>
+  %cmp = icmp ne <3 x i64> %b, <i64 0, i64 undef, i64 0>
+  ret <3 x i1> %cmp
+}
+
+define i1 @i32_cast_cmp_eq_int_0_uitofp_half(i32 %i) {
+; CHECK-LABEL: @i32_cast_cmp_eq_int_0_uitofp_half(
+; CHECK-NEXT:    [[F:%.*]] = uitofp i32 [[I:%.*]] to half
+; CHECK-NEXT:    [[B:%.*]] = bitcast half [[F]] to i16
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i16 [[B]], 0
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %f = uitofp i32 %i to half
+  %b = bitcast half %f to i16
+  %cmp = icmp eq i16 %b, 0
+  ret i1 %cmp
+}
+
+define <2 x i1> @i32_cast_cmp_eq_int_0_uitofp_half_vec(<2 x i32> %i) {
+; CHECK-LABEL: @i32_cast_cmp_eq_int_0_uitofp_half_vec(
+; CHECK-NEXT:    [[F:%.*]] = uitofp <2 x i32> [[I:%.*]] to <2 x half>
+; CHECK-NEXT:    [[B:%.*]] = bitcast <2 x half> [[F]] to <2 x i16>
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq <2 x i16> [[B]], zeroinitializer
+; CHECK-NEXT:    ret <2 x i1> [[CMP]]
+;
+  %f = uitofp <2 x i32> %i to  <2 x half>
+  %b = bitcast <2 x half> %f to <2 x i16>
+  %cmp = icmp eq <2 x i16> %b, <i16 0, i16 0>
+  ret <2 x i1> %cmp
+}
+
+define <3 x i1> @i32_cast_cmp_eq_int_0_uitofp_half_vec_undef(<3 x i32> %i) {
+; CHECK-LABEL: @i32_cast_cmp_eq_int_0_uitofp_half_vec_undef(
+; CHECK-NEXT:    [[F:%.*]] = uitofp <3 x i32> [[I:%.*]] to <3 x half>
+; CHECK-NEXT:    [[B:%.*]] = bitcast <3 x half> [[F]] to <3 x i16>
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq <3 x i16> [[B]], <i16 0, i16 undef, i16 0>
+; CHECK-NEXT:    ret <3 x i1> [[CMP]]
+;
+  %f = uitofp <3 x i32> %i to <3 x half>
+  %b = bitcast <3 x half> %f to <3 x i16>
+  %cmp = icmp eq <3 x i16> %b, <i16 0, i16 undef, i16 0>
+  ret <3 x i1> %cmp
+}
+
+define i1 @i32_cast_cmp_ne_int_0_uitofp_half(i32 %i) {
+; CHECK-LABEL: @i32_cast_cmp_ne_int_0_uitofp_half(
+; CHECK-NEXT:    [[F:%.*]] = uitofp i32 [[I:%.*]] to half
+; CHECK-NEXT:    [[B:%.*]] = bitcast half [[F]] to i16
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i16 [[B]], 0
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %f = uitofp i32 %i to half
+  %b = bitcast half %f to i16
+  %cmp = icmp ne i16 %b, 0
+  ret i1 %cmp
+}
+
+define <2 x i1> @i32_cast_cmp_ne_int_0_uitofp_half_vec(<2 x i32> %i) {
+; CHECK-LABEL: @i32_cast_cmp_ne_int_0_uitofp_half_vec(
+; CHECK-NEXT:    [[F:%.*]] = uitofp <2 x i32> [[I:%.*]] to <2 x half>
+; CHECK-NEXT:    [[B:%.*]] = bitcast <2 x half> [[F]] to <2 x i16>
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne <2 x i16> [[B]], zeroinitializer
+; CHECK-NEXT:    ret <2 x i1> [[CMP]]
+;
+  %f = uitofp <2 x i32> %i to  <2 x half>
+  %b = bitcast <2 x half> %f to <2 x i16>
+  %cmp = icmp ne <2 x i16> %b, <i16 0, i16 0>
+  ret <2 x i1> %cmp
+}
+
+define <3 x i1> @i32_cast_cmp_ne_int_0_uitofp_half_vec_undef(<3 x i32> %i) {
+; CHECK-LABEL: @i32_cast_cmp_ne_int_0_uitofp_half_vec_undef(
+; CHECK-NEXT:    [[F:%.*]] = uitofp <3 x i32> [[I:%.*]] to <3 x half>
+; CHECK-NEXT:    [[B:%.*]] = bitcast <3 x half> [[F]] to <3 x i16>
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne <3 x i16> [[B]], <i16 0, i16 undef, i16 0>
+; CHECK-NEXT:    ret <3 x i1> [[CMP]]
+;
+  %f = uitofp <3 x i32> %i to <3 x half>
+  %b = bitcast <3 x half> %f to <3 x i16>
+  %cmp = icmp ne <3 x i16> %b, <i16 0, i16 undef, i16 0>
+  ret <3 x i1> %cmp
+}