[llvm] Remove br i1 undef from some regression tests [NFC] (#118419)

This PR removes tests with `br i1 undef` under
`llvm/tests/Transforms/ObjCARC, Reassociate, SCCP, SLPVectorizer...`.
After this PR, I'll continue to fix tests under `llvm/tests/CodeGen`,
which has more UB tests than `llvm/tests/Transforms`.

Author: leewei05

llvm/test/Transforms/ObjCARC/allocas.ll

@@ -109,16 +109,16 @@ entry:
 }
 
 
-; CHECK: define void @test1d(ptr %x)
+; CHECK: define void @test1d(ptr %x, i1 %arg)
 ; CHECK: @llvm.objc.retain(ptr %x)
 ; CHECK: @llvm.objc.retain(ptr %x)
 ; CHECK: @llvm.objc.release(ptr %y)
 ; CHECK: @llvm.objc.release(ptr %x)
 ; CHECK: ret void
 ; CHECK: }
-define void @test1d(ptr %x) {
+define void @test1d(ptr %x, i1 %arg) {
 entry:
-  br i1 undef, label %use_allocaA, label %use_allocaB
+  br i1 %arg, label %use_allocaA, label %use_allocaB
 
 use_allocaA:
   %allocaA = alloca ptr
@@ -141,16 +141,16 @@ exit:
   ret void
 }
 
-; CHECK: define void @test1e(ptr %x)
+; CHECK: define void @test1e(ptr %x, i1 %arg)
 ; CHECK: @llvm.objc.retain(ptr %x)
 ; CHECK: @llvm.objc.retain(ptr %x)
 ; CHECK: @llvm.objc.release(ptr %y)
 ; CHECK: @llvm.objc.release(ptr %x)
 ; CHECK: ret void
 ; CHECK: }
-define void @test1e(ptr %x) {
+define void @test1e(ptr %x, i1 %arg) {
 entry:
-  br i1 undef, label %use_allocaA, label %use_allocaB
+  br i1 %arg, label %use_allocaA, label %use_allocaB
 
 use_allocaA:
   %allocaA = alloca ptr, i32 4

llvm/test/Transforms/ObjCARC/basic.ll

@@ -1761,13 +1761,13 @@ g:
 ; CHECK-LABEL: define void @test39(
 ; CHECK-NOT: @llvm.objc.
 ; CHECK: {{^}}}
-define void @test39(ptr %p) {
+define void @test39(ptr %p, i1 %arg) {
 entry:
   %0 = call ptr @llvm.objc.retain(ptr %p)
   br label %loop
 
 loop:                                             ; preds = %loop, %entry
-  br i1 undef, label %loop, label %exit
+  br i1 %arg, label %loop, label %exit
 
 exit:                                             ; preds = %loop
   call void @llvm.objc.release(ptr %0), !clang.imprecise_release !0
@@ -1779,14 +1779,14 @@ exit:                                             ; preds = %loop
 ; CHECK-LABEL: define void @test39b(
 ; CHECK-NOT: @llvm.objc.
 ; CHECK: {{^}}}
-define void @test39b(ptr %p) {
+define void @test39b(ptr %p, i1 %arg) {
 entry:
   %0 = call ptr @llvm.objc.retain(ptr %p)
   br label %loop
 
 loop:                                             ; preds = %loop, %entry
   store i8 0, ptr %0
-  br i1 undef, label %loop, label %exit
+  br i1 %arg, label %loop, label %exit
 
 exit:                                             ; preds = %loop
   call void @llvm.objc.release(ptr %0), !clang.imprecise_release !0
@@ -1798,14 +1798,14 @@ exit:                                             ; preds = %loop
 ; CHECK-LABEL: define void @test39c(
 ; CHECK-NOT: @llvm.objc.
 ; CHECK: {{^}}}
-define void @test39c(ptr %p) {
+define void @test39c(ptr %p, i1 %arg) {
 entry:
   %0 = call ptr @llvm.objc.retain(ptr %p)
   br label %loop
 
 loop:                                             ; preds = %loop, %entry
   call void @use_pointer(ptr %0)
-  br i1 undef, label %loop, label %exit
+  br i1 %arg, label %loop, label %exit
 
 exit:                                             ; preds = %loop
   call void @llvm.objc.release(ptr %0), !clang.imprecise_release !0
@@ -1818,14 +1818,14 @@ exit:                                             ; preds = %loop
 ; CHECK-LABEL: define void @test40(
 ; CHECK-NOT: @llvm.objc.
 ; CHECK: {{^}}}
-define void @test40(ptr %p) {
+define void @test40(ptr %p, i1 %arg) {
 entry:
   %0 = call ptr @llvm.objc.retain(ptr %p)
   br label %loop
 
 loop:                                             ; preds = %loop, %entry
   call void @use_pointer(ptr %0)
-  br i1 undef, label %exit, label %loop
+  br i1 %arg, label %exit, label %loop
 
 exit:                                             ; preds = %loop
   call void @llvm.objc.release(ptr %0), !clang.imprecise_release !0