[ConstraintElimination] Remove over-eager assertion.

After moving the CanAdd check in c60cdb4 and using it for
the assume cases as well, the passed in block may not have  a branch
instruction as terminator. This can trigger the assertion. Given the new
use case, it doesn't add value any longer and can be removed.

Fixes llvm#54281

Author: fhahn

llvm/lib/Transforms/Scalar/ConstraintElimination.cpp

@@ -275,7 +275,6 @@ static bool eliminateConstraints(Function &F, DominatorTree &DT) {
     // Succ (e.g. the case when adding a condition from a pre-header to a loop
     // header).
     auto CanAdd = [&BB, &DT](BasicBlock *Succ) {
-      assert(isa<BranchInst>(BB.getTerminator()));
       return any_of(successors(&BB),
                     [Succ](const BasicBlock *S) { return S != Succ; }) &&
              all_of(predecessors(Succ), [&BB, &DT, Succ](BasicBlock *Pred) {

llvm/test/Transforms/ConstraintElimination/invoke.ll

@@ -0,0 +1,50 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -passes=constraint-elimination -S %s | FileCheck %s
+
+declare void @may_unwind()
+
+declare i32 @__gxx_personality_v0(...);
+
+define i1 @test_invoke_in_block_with_assume(i32 %x) personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {
+; CHECK-LABEL: @test_invoke_in_block_with_assume(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    call void @may_unwind()
+; CHECK-NEXT:    [[C_1:%.*]] = icmp ult i32 [[X:%.*]], 10
+; CHECK-NEXT:    call void @llvm.assume(i1 [[C_1]])
+; CHECK-NEXT:    invoke void @may_unwind()
+; CHECK-NEXT:    to label [[CONT:%.*]] unwind label [[LPAD:%.*]]
+; CHECK:       cont:
+; CHECK-NEXT:    [[T_1:%.*]] = icmp ult i32 [[X]], 10
+; CHECK-NEXT:    [[C_2:%.*]] = icmp ult i32 [[X]], 9
+; CHECK-NEXT:    [[RES_1:%.*]] = xor i1 true, [[C_2]]
+; CHECK-NEXT:    ret i1 [[RES_1]]
+; CHECK:       lpad:
+; CHECK-NEXT:    [[LP:%.*]] = landingpad { i8*, i32 }
+; CHECK-NEXT:    filter [0 x i8*] zeroinitializer
+; CHECK-NEXT:    [[T_2:%.*]] = icmp ult i32 [[X]], 10
+; CHECK-NEXT:    [[C_3:%.*]] = icmp ult i32 [[X]], 9
+; CHECK-NEXT:    [[RES_2:%.*]] = xor i1 true, [[C_3]]
+; CHECK-NEXT:    ret i1 [[RES_2]]
+;
+entry:
+  call void @may_unwind()
+  %c.1 = icmp ult i32 %x, 10
+  call void @llvm.assume(i1 %c.1)
+  invoke void @may_unwind() to label %cont unwind label %lpad
+
+cont:
+  %t.1 = icmp ult i32 %x, 10
+  %c.2 = icmp ult i32 %x, 9
+  %res.1 = xor i1 %t.1, %c.2
+  ret i1 %res.1
+
+lpad:
+  %lp = landingpad { i8*, i32 }
+  filter [0 x i8*] zeroinitializer
+  %t.2 = icmp ult i32 %x, 10
+  %c.3 = icmp ult i32 %x, 9
+  %res.2 = xor i1 %t.2, %c.3
+  ret i1 %res.2
+}
+
+declare void @llvm.assume(i1)

llvm/test/Transforms/ConstraintElimination/switch.ll

@@ -0,0 +1,47 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -passes=constraint-elimination -S %s | FileCheck %s
+
+declare void @may_unwind()
+
+define i1 @test_switch_in_block_with_assume(i32 %x) {
+; CHECK-LABEL: @test_switch_in_block_with_assume(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    call void @may_unwind()
+; CHECK-NEXT:    [[C_1:%.*]] = icmp ult i32 [[X:%.*]], 10
+; CHECK-NEXT:    call void @llvm.assume(i1 [[C_1]])
+; CHECK-NEXT:    switch i32 0, label [[EXIT_1:%.*]] [
+; CHECK-NEXT:    i32 1, label [[EXIT_2:%.*]]
+; CHECK-NEXT:    ]
+; CHECK:       exit.1:
+; CHECK-NEXT:    [[T_1:%.*]] = icmp ult i32 [[X]], 10
+; CHECK-NEXT:    [[C_2:%.*]] = icmp ult i32 [[X]], 9
+; CHECK-NEXT:    [[RES_1:%.*]] = xor i1 true, [[C_2]]
+; CHECK-NEXT:    ret i1 [[RES_1]]
+; CHECK:       exit.2:
+; CHECK-NEXT:    [[T_2:%.*]] = icmp ult i32 [[X]], 10
+; CHECK-NEXT:    [[C_3:%.*]] = icmp ult i32 [[X]], 9
+; CHECK-NEXT:    [[RES_2:%.*]] = xor i1 true, [[C_3]]
+; CHECK-NEXT:    ret i1 [[RES_2]]
+;
+entry:
+  call void @may_unwind()
+  %c.1 = icmp ult i32 %x, 10
+  call void @llvm.assume(i1 %c.1)
+  switch i32 0, label %exit.1 [
+  i32 1, label %exit.2
+  ]
+
+exit.1:
+  %t.1 = icmp ult i32 %x, 10
+  %c.2 = icmp ult i32 %x, 9
+  %res.1 = xor i1 %t.1, %c.2
+  ret i1 %res.1
+
+exit.2:
+  %t.2 = icmp ult i32 %x, 10
+  %c.3 = icmp ult i32 %x, 9
+  %res.2 = xor i1 %t.2, %c.3
+  ret i1 %res.2
+}
+
+declare void @llvm.assume(i1)