[InstCombine][NFC] Add tests with icmp splat vectors and B masks

[jmciver]

Summary

Add tests to verifying future support for splat vectors containing poison/undef
in llvm::decomposeBitTestICmp.

[jmciver]

Fix label naming error

[jmciver]

Convert splat vectors from undef to poison

[jmciver]

Rebase onto latest main.

[RKSimon]

LGTM

[jmciver]

@RKSimon thanks for taking the time to review the patch!

I have recently requested repository access. In the interim can you please land this patch for me?

Name: John McIver
Email: [e-mail]

llvm/test/Transforms/InstCombine/icmp-logical.ll

 ;
   %t1 = and i32 %x, 2147483647
   %t2 = icmp ne i32 %t1, 0
   %t3 = icmp ne i32 %x, 2147483647
   %t4 = select i1 %t3, i1 true, i1 %t2
   ret i1 %t4
 }
 
+define <2 x i1> @nomask_splat_and_B_allones(<2 x i32> %A) {
+; CHECK-LABEL: @nomask_splat_and_B_allones(
+; CHECK-NEXT:    [[TST1:%.*]] = icmp slt <2 x i32> [[A:%.*]], <i32 0, i32 undef>
+; CHECK-NEXT:    [[MASK2:%.*]] = and <2 x i32> [[A]], <i32 1879048192, i32 1879048192>
+; CHECK-NEXT:    [[TST2:%.*]] = icmp eq <2 x i32> [[MASK2]], <i32 1879048192, i32 1879048192>
+; CHECK-NEXT:    [[RES:%.*]] = and <2 x i1> [[TST1]], [[TST2]]
+; CHECK-NEXT:    ret <2 x i1> [[RES]]
+;
+  %tst1 = icmp slt <2 x i32> %A, <i32 0, i32 undef>
+  %mask2 = and <2 x i32> %A, <i32 1879048192, i32 1879048192>
+  %tst2 = icmp eq <2 x i32> %mask2, <i32 1879048192, i32 1879048192>
+  %res = and <2 x i1> %tst1, %tst2
+  ret <2 x i1> %res
+}
+
+define <2 x i1> @nomask_splat_and_B_mixed(<2 x i32> %A) {
+; CHECK-LABEL: @nomask_splat_and_B_mixed(
+; CHECK-NEXT:    [[TST1:%.*]] = icmp sgt <2 x i32> [[A:%.*]], <i32 -1, i32 undef>
+; CHECK-NEXT:    [[MASK2:%.*]] = and <2 x i32> [[A]], <i32 1879048192, i32 1879048192>
+; CHECK-NEXT:    [[TST2:%.*]] = icmp eq <2 x i32> [[MASK2]], <i32 1879048192, i32 1879048192>
+; CHECK-NEXT:    [[RES:%.*]] = and <2 x i1> [[TST1]], [[TST2]]
+; CHECK-NEXT:    ret <2 x i1> [[RES]]
+;
+  %tst1 = icmp sgt <2 x i32> %A, <i32 -1, i32 undef>
+  %mask2 = and <2 x i32> %A, <i32 1879048192, i32 1879048192>
+  %tst2 = icmp eq <2 x i32> %mask2, <i32 1879048192, i32 1879048192>
+  %res = and <2 x i1> %tst1, %tst2
+  ret <2 x i1> %res
+}
+
 ; PR32401 - https://bugs.llvm.org/show_bug.cgi?id=32401
 
 define i1 @cmpeq_bitwise(i8 %a, i8 %b, i8 %c, i8 %d) {
 ; CHECK-LABEL: @cmpeq_bitwise(
 ; CHECK-NEXT:    [[TMP1:%.*]] = icmp eq i8 [[A:%.*]], [[B:%.*]]
 ; CHECK-NEXT:    [[TMP2:%.*]] = icmp eq i8 [[C:%.*]], [[D:%.*]]
 ; CHECK-NEXT:    [[CMP:%.*]] = and i1 [[TMP1]], [[TMP2]]
 ; CHECK-NEXT:    ret i1 [[CMP]]