[InstSimplify] move tests for select from InstCombine; NFC

InstCombine has transforms that would enable these simplifications
in an indirect way, but those transforms are unsafe and likely to
be removed.

Author: rotateright

llvm/test/Transforms/InstCombine/select.ll

@@ -5,39 +5,6 @@
 
 target datalayout = "e-p:64:64-p1:16:16-p2:32:32:32-p3:64:64:64"
 
-define i32 @test1(i32 %A, i32 %B) {
-; CHECK-LABEL: @test1(
-; CHECK-NEXT:    ret i32 [[B:%.*]]
-;
-  %C = select i1 false, i32 %A, i32 %B
-  ret i32 %C
-}
-
-define i32 @test2(i32 %A, i32 %B) {
-; CHECK-LABEL: @test2(
-; CHECK-NEXT:    ret i32 [[A:%.*]]
-;
-  %C = select i1 true, i32 %A, i32 %B
-  ret i32 %C
-}
-
-
-define i32 @test3(i1 %C, i32 %I) {
-; CHECK-LABEL: @test3(
-; CHECK-NEXT:    ret i32 [[I:%.*]]
-;
-  %V = select i1 %C, i32 %I, i32 %I
-  ret i32 %V
-}
-
-define i1 @test4(i1 %C) {
-; CHECK-LABEL: @test4(
-; CHECK-NEXT:    ret i1 [[C:%.*]]
-;
-  %V = select i1 %C, i1 true, i1 false
-  ret i1 %V
-}
-
 define i1 @test5(i1 %C) {
 ; CHECK-LABEL: @test5(
 ; CHECK-NEXT:    [[NOT_C:%.*]] = xor i1 [[C:%.*]], true

llvm/test/Transforms/InstSimplify/select.ll

@@ -25,6 +25,30 @@ define <2 x i1> @bool_true_or_false_vec_undef(<2 x i1> %cond) {
   ret <2 x i1> %s
 }
 
+define i32 @cond_is_false(i32 %A, i32 %B) {
+; CHECK-LABEL: @cond_is_false(
+; CHECK-NEXT:    ret i32 [[B:%.*]]
+;
+  %C = select i1 false, i32 %A, i32 %B
+  ret i32 %C
+}
+
+define i32 @cond_is_true(i32 %A, i32 %B) {
+; CHECK-LABEL: @cond_is_true(
+; CHECK-NEXT:    ret i32 [[A:%.*]]
+;
+  %C = select i1 true, i32 %A, i32 %B
+  ret i32 %C
+}
+
+define i32 @equal_arms(i1 %C, i32 %I) {
+; CHECK-LABEL: @equal_arms(
+; CHECK-NEXT:    ret i32 [[I:%.*]]
+;
+  %V = select i1 %C, i32 %I, i32 %I
+  ret i32 %V
+}
+
 define <2 x i8> @vsel_tvec(<2 x i8> %x, <2 x i8> %y) {
 ; CHECK-LABEL: @vsel_tvec(
 ; CHECK-NEXT:    ret <2 x i8> [[X:%.*]]