[InstCombine] add tests for select with frozen condition; NFC

Author: rotateright

llvm/test/Transforms/InstCombine/select.ll

@@ -2595,33 +2595,53 @@ define i8 @cond_freeze(i8 %x, i8 %y) {
   ret i8 %s
 }
 
-define i8 @cond_freeze2(i8 %x, i8 %y) {
-; CHECK-LABEL: @cond_freeze2(
+define i8 @cond_freeze_constant_false_val(i8 %x) {
+; CHECK-LABEL: @cond_freeze_constant_false_val(
 ; CHECK-NEXT:    ret i8 1
 ;
   %cond.fr = freeze i1 undef
   %s = select i1 %cond.fr, i8 %x, i8 1
   ret i8 %s
 }
 
-define i8 @cond_freeze3(i8 %x) {
-; CHECK-LABEL: @cond_freeze3(
+define i8 @cond_freeze_constant_true_val(i8 %x) {
+; CHECK-LABEL: @cond_freeze_constant_true_val(
 ; CHECK-NEXT:    ret i8 1
 ;
   %cond.fr = freeze i1 undef
   %s = select i1 %cond.fr, i8 1, i8 %x
   ret i8 %s
 }
 
-define <2 x i8> @cond_freeze_vec(<2 x i8> %x) {
-; CHECK-LABEL: @cond_freeze_vec(
+define i8 @cond_freeze_both_arms_constant() {
+; CHECK-LABEL: @cond_freeze_both_arms_constant(
+; CHECK-NEXT:    ret i8 3
+;
+  %cond.fr = freeze i1 undef
+  %s = select i1 %cond.fr, i8 42, i8 3
+  ret i8 %s
+}
+
+define <2 x i8> @cond_freeze_constant_true_val_vec(<2 x i8> %x) {
+; CHECK-LABEL: @cond_freeze_constant_true_val_vec(
 ; CHECK-NEXT:    ret <2 x i8> <i8 1, i8 2>
 ;
   %cond.fr = freeze <2 x i1> <i1 undef, i1 undef>
   %s = select <2 x i1> %cond.fr, <2 x i8> <i8 1, i8 2>, <2 x i8> %x
   ret <2 x i8> %s
 }
 
+define <2 x i8> @partial_cond_freeze_constant_true_val_vec(<2 x i8> %x) {
+; CHECK-LABEL: @partial_cond_freeze_constant_true_val_vec(
+; CHECK-NEXT:    [[COND_FR:%.*]] = freeze <2 x i1> <i1 true, i1 undef>
+; CHECK-NEXT:    [[S:%.*]] = select <2 x i1> [[COND_FR]], <2 x i8> <i8 1, i8 2>, <2 x i8> [[X:%.*]]
+; CHECK-NEXT:    ret <2 x i8> [[S]]
+;
+  %cond.fr = freeze <2 x i1> <i1 true, i1 undef>
+  %s = select <2 x i1> %cond.fr, <2 x i8> <i8 1, i8 2>, <2 x i8> %x
+  ret <2 x i8> %s
+}
+
 declare void @foo2(i8, i8)
 
 define void @cond_freeze_multipleuses(i8 %x, i8 %y) {