[CIR][CodeGen] Emit RunCleanupsScope's dtor properly for ExprWithCleanups

[bruteforceboy]

The following code snippet crashes during CIR CodeGen using clang tmp.cpp -Xclang -emit-cir -S -o -:

#include <vector>

void foo() {
  std::vector<int> v(1);
}

The crash is:

mlir::Operation* mlir::Block::getTerminator(): Assertion `mightHaveTerminator()' failed.

What happens is the scope created here is malformed. The operations inside the scope using --mlir-print-assume-verified looks something like:

%0 = cir.alloca !cir.record<class "std::allocator<int>" padded {!cir.int<u, 8>} #cir.record.decl.ast>, !cir.ptr<!cir.record<class "std::allocator<int>" padded {!cir.int<u, 8>} #cir.record.decl.ast>>, ["ref.tmp0"] {alignment = 1 : i64}
%1 = cir.load <<UNKNOWN SSA VALUE>> : !cir.ptr<!cir.int<u, 64>>, !cir.int<u, 64>
%2 = cir.load <<UNKNOWN SSA VALUE>> : !cir.ptr<!cir.ptr<!cir.record<class "std::allocator<int>" padded {!cir.int<u, 8>} #cir.record.decl.ast>>>, !cir.ptr<!cir.record<class "std::allocator<int>" padded {!cir.int<u, 8>} #cir.record.decl.ast>>
cir.call @_ZNSaIiEC1ERKS_(%0, %2) : (!cir.ptr<!cir.record<class "std::allocator<int>" padded {!cir.int<u, 8>} #cir.record.decl.ast>>, !cir.ptr<!cir.record<class "std::allocator<int>" padded {!cir.int<u, 8>} #cir.record.decl.ast>>) -> () extra(#cir<extra({nothrow = #cir.nothrow})>)
%3 = cir.call @_ZNSt6vectorIiSaIiEE11_S_max_sizeERKS0_(%0) : (!cir.ptr<!cir.record<class "std::allocator<int>" padded {!cir.int<u, 8>} #cir.record.decl.ast>>) -> !cir.int<u, 64> extra(#cir<extra({nothrow = #cir.nothrow})>)
%4 = cir.cmp(gt, %1, %3) : !cir.int<u, 64>, !cir.bool
cir.yield %4 : !cir.bool              
cir.call @_ZNSaIiED1Ev(%0) : (!cir.ptr<!cir.record<class "std::allocator<int>" padded {!cir.int<u, 8>} #cir.record.decl.ast>>) -> () extra(#cir<extra({nothrow = #cir.nothrow})>)

_ZNSaIiED1Ev is std::allocator<int>::~allocator(). So, the destructor comes after the YieldOp has been created, which is wrong. The destructor comes from the destruction of RunCleanupScope since LexicalScope inherits from it. RunCleanupsScope's dtor should come before the yield is created!

This PR fixes this by calling ForceCleanup before creating the yield, so the YieldOp becomes the last operation in the scope. I found this bug using the code snippet above, but I have added a reduced version, using creduce, as a test, because std-cxx.h doesn't quite replicate std::vector correctly.

[bcardosolopes]

LGTM, one minor nit

[bcardosolopes]

Looks like tests are failing

[bruteforceboy]

Looks like tests are failing

Oh, I didn't notice ( It seems this PR#1580 made quite a number of changes. I will update the test in a few hours.