[InstCombine] Add tests for selects with same conditions (NFC)

Author: vfdff

llvm/test/Transforms/InstCombine/select.ll

@@ -3706,3 +3706,59 @@ define i32 @src_select_xxory_eq0_xorxy_y(i32 %x, i32 %y) {
   %cond = select i1 %xor0, i32 %xor, i32 %y
   ret i32 %cond
 }
+
+define i32 @sequence_select_with_same_cond_false(i1 %c1, i1 %c2){
+; CHECK-LABEL: @sequence_select_with_same_cond_false(
+; CHECK-NEXT:    [[S1:%.*]] = select i1 [[C1:%.*]], i32 23, i32 45
+; CHECK-NEXT:    [[S2:%.*]] = select i1 [[C2:%.*]], i32 666, i32 [[S1]]
+; CHECK-NEXT:    [[S3:%.*]] = select i1 [[C1]], i32 789, i32 [[S2]]
+; CHECK-NEXT:    ret i32 [[S3]]
+;
+  %s1 = select i1 %c1, i32 23, i32 45
+  %s2 = select i1 %c2, i32 666, i32 %s1
+  %s3 = select i1 %c1, i32 789, i32 %s2
+  ret i32 %s3
+}
+
+define i32 @sequence_select_with_same_cond_true(i1 %c1, i1 %c2){
+; CHECK-LABEL: @sequence_select_with_same_cond_true(
+; CHECK-NEXT:    [[S1:%.*]] = select i1 [[C1:%.*]], i32 45, i32 23
+; CHECK-NEXT:    [[S2:%.*]] = select i1 [[C2:%.*]], i32 [[S1]], i32 666
+; CHECK-NEXT:    [[S3:%.*]] = select i1 [[C1]], i32 [[S2]], i32 789
+; CHECK-NEXT:    ret i32 [[S3]]
+;
+  %s1 = select i1 %c1, i32 45, i32 23
+  %s2 = select i1 %c2, i32 %s1, i32 666
+  %s3 = select i1 %c1, i32 %s2, i32 789
+  ret i32 %s3
+}
+
+define double @sequence_select_with_same_cond_double(double %a, i1 %c1, i1 %c2, double %r1, double %r2){
+; CHECK-LABEL: @sequence_select_with_same_cond_double(
+; CHECK-NEXT:    [[S1:%.*]] = select i1 [[C1:%.*]], double 1.000000e+00, double 0.000000e+00
+; CHECK-NEXT:    [[S2:%.*]] = select i1 [[C2:%.*]], double [[S1]], double 2.000000e+00
+; CHECK-NEXT:    [[S3:%.*]] = select i1 [[C1]], double [[S2]], double 3.000000e+00
+; CHECK-NEXT:    ret double [[S3]]
+;
+  %s1 = select i1 %c1, double 1.0, double 0.0
+  %s2 = select i1 %c2, double %s1, double 2.0
+  %s3 = select i1 %c1, double %s2, double 3.0
+  ret double %s3
+}
+
+declare void @use32(i32)
+
+define i32 @sequence_select_with_same_cond_extra_use(i1 %c1, i1 %c2){
+; CHECK-LABEL: @sequence_select_with_same_cond_extra_use(
+; CHECK-NEXT:    [[S1:%.*]] = select i1 [[C1:%.*]], i32 23, i32 45
+; CHECK-NEXT:    call void @use32(i32 [[S1]])
+; CHECK-NEXT:    [[S2:%.*]] = select i1 [[C2:%.*]], i32 666, i32 [[S1]]
+; CHECK-NEXT:    [[S3:%.*]] = select i1 [[C1]], i32 789, i32 [[S2]]
+; CHECK-NEXT:    ret i32 [[S3]]
+;
+  %s1 = select i1 %c1, i32 23, i32 45
+  call void @use32(i32 %s1)
+  %s2 = select i1 %c2, i32 666, i32 %s1
+  %s3 = select i1 %c1, i32 789, i32 %s2
+  ret i32 %s3
+}