[ownership] Ban cond_br from having any non-trivial operands.

Previously, we just banned cond_br from having non-trivial operands along
critical edges. This is a stronger condition that beyond simplifying ossa for
passes, also lets me remove the need for BranchPropagatedUser, simplifying the
linear lifetime checker.

Author: gottesmm

lib/SIL/SILVerifier.cpp

@@ -4303,37 +4303,46 @@ class SILVerifier : public SILVerifierBase<SILVerifier> {
             "branch argument types do not match arguments for dest bb");
   }
 
-  void checkCondBranchInst(CondBranchInst *CBI) {
+  void checkCondBranchInst(CondBranchInst *cbi) {
     // It is important that cond_br keeps an i1 type. ARC Sequence Opts assumes
     // that cond_br does not use reference counted values or decrement reference
     // counted values under the assumption that the instruction that computes
     // the i1 is the use/decrement that ARC cares about and that after that
     // instruction is evaluated, the scalar i1 has a different identity and the
     // object can be deallocated.
-    requireSameType(CBI->getCondition()->getType(),
+    requireSameType(cbi->getCondition()->getType(),
                     SILType::getBuiltinIntegerType(
-                        1, CBI->getCondition()->getType().getASTContext()),
+                        1, cbi->getCondition()->getType().getASTContext()),
                     "condition of conditional branch must have Int1 type");
 
-    require(CBI->getTrueArgs().size() == CBI->getTrueBB()->args_size(),
+    require(cbi->getTrueArgs().size() == cbi->getTrueBB()->args_size(),
             "true branch has wrong number of arguments for dest bb");
-    require(CBI->getTrueBB() != CBI->getFalseBB(),
-            "identical destinations");
-    require(std::equal(CBI->getTrueArgs().begin(), CBI->getTrueArgs().end(),
-                       CBI->getTrueBB()->args_begin(),
+    require(cbi->getTrueBB() != cbi->getFalseBB(), "identical destinations");
+    require(std::equal(cbi->getTrueArgs().begin(), cbi->getTrueArgs().end(),
+                       cbi->getTrueBB()->args_begin(),
                        [&](SILValue branchArg, SILArgument *bbArg) {
                          return verifyBranchArgs(branchArg, bbArg);
                        }),
             "true branch argument types do not match arguments for dest bb");
 
-    require(CBI->getFalseArgs().size() == CBI->getFalseBB()->args_size(),
+    require(cbi->getFalseArgs().size() == cbi->getFalseBB()->args_size(),
             "false branch has wrong number of arguments for dest bb");
-    require(std::equal(CBI->getFalseArgs().begin(), CBI->getFalseArgs().end(),
-                       CBI->getFalseBB()->args_begin(),
+    require(std::equal(cbi->getFalseArgs().begin(), cbi->getFalseArgs().end(),
+                       cbi->getFalseBB()->args_begin(),
                        [&](SILValue branchArg, SILArgument *bbArg) {
                          return verifyBranchArgs(branchArg, bbArg);
                        }),
             "false branch argument types do not match arguments for dest bb");
+    // When we are in ossa, cond_br can not have any arguments that are
+    // non-trivial.
+    if (!F.hasOwnership())
+      return;
+
+    require(llvm::all_of(cbi->getOperandValues(),
+                         [&](SILValue v) -> bool {
+                           return v->getType().isTrivial(*cbi->getFunction());
+                         }),
+            "cond_br must not have a non-trivial value in ossa.");
   }
 
   void checkDynamicMethodBranchInst(DynamicMethodBranchInst *DMBI) {
@@ -4905,38 +4914,13 @@ class SILVerifier : public SILVerifierBase<SILVerifier> {
       CurInstruction = TI;
 
       // Check for non-cond_br critical edges.
-      auto *CBI = dyn_cast<CondBranchInst>(TI);
-      if (!CBI) {
-        for (unsigned Idx = 0, e = BB.getSuccessors().size(); Idx != e; ++Idx) {
-          require(!isCriticalEdgePred(TI, Idx),
-                  "non cond_br critical edges not allowed");
-        }
+      if (isa<CondBranchInst>(TI)) {
         continue;
       }
-      // In ownership qualified SIL, ban critical edges from CondBranchInst that
-      // have non-trivial arguments.
-      //
-      // FIXME: it would be far simpler to ban all critical edges in general.
-      if (!F->hasOwnership())
-        continue;
 
-      if (isCriticalEdgePred(CBI, CondBranchInst::TrueIdx)) {
-        require(
-            llvm::all_of(CBI->getTrueArgs(),
-                         [](SILValue V) -> bool {
-                           return V.getOwnershipKind() ==
-                                  ValueOwnershipKind::None;
-                         }),
-            "cond_br with critical edges must not have a non-trivial value");
-      }
-      if (isCriticalEdgePred(CBI, CondBranchInst::FalseIdx)) {
-        require(
-            llvm::all_of(CBI->getFalseArgs(),
-                         [](SILValue V) -> bool {
-                           return V.getOwnershipKind() ==
-                                  ValueOwnershipKind::None;
-                         }),
-            "cond_br with critical edges must not have a non-trivial value");
+      for (unsigned Idx = 0, e = BB.getSuccessors().size(); Idx != e; ++Idx) {
+        require(!isCriticalEdgePred(TI, Idx),
+                "non cond_br critical edges not allowed");
       }
     }
   }

test/SIL/ownership-verifier/arguments.sil

@@ -474,54 +474,6 @@ bb1(%1 : @owned $Builtin.NativeObject):
   return %9999 : $()
 }
 
-// CHECK-LABEL: Function: 'owned_argument_overuse_condbr1'
-// CHECK-NEXT: Found over consume?!
-// CHECK-NEXT: Value: %0 = argument of bb0 : $Builtin.NativeObject
-// CHECK-NEXT: User:   cond_br undef, bb1(%0 : $Builtin.NativeObject), bb2
-// CHECK-NEXT: Block: bb0
-//
-// CHECK-LABEL: Function: 'owned_argument_overuse_condbr1'
-// CHECK-NEXT: Error! Found a leak due to a consuming post-dominance failure!
-// CHECK-NEXT: Value: %0 = argument of bb0
-// CHECK-NEXT: Post Dominating Failure Blocks:
-// CHECK-NEXT: bb2
-//
-// CHECK-LABEL: Function: 'owned_argument_overuse_condbr1'
-// CHECK-NEXT: Error! Found a leaked owned value that was never consumed.
-// CHECK-NEXT: Value: %3 = argument of bb1 : $Builtin.NativeObject
-// CHECK-NOT: Function: 'owned_argument_overuse_condbr1'
-sil [ossa] @owned_argument_overuse_condbr1 : $@convention(thin) (@owned Builtin.NativeObject) -> () {
-bb0(%0 : @owned $Builtin.NativeObject):
-  destroy_value %0 : $Builtin.NativeObject
-  cond_br undef, bb1(%0 : $Builtin.NativeObject), bb2
-
-bb1(%1 : @owned $Builtin.NativeObject):
-  br bb2
-
-bb2:
-  %9999 = tuple()
-  return %9999 : $()
-}
-
-// CHECK-LABEL: Function: 'owned_argument_overuse_condbr2'
-// CHECK-NEXT: Found over consume?!
-// CHECK-NEXT: Value: %0 = argument of bb0 : $Builtin.NativeObject
-// CHECK-NEXT: User:   cond_br undef, bb1(%0 : $Builtin.NativeObject), bb2
-// CHECK-NEXT: Block: bb0
-sil [ossa] @owned_argument_overuse_condbr2 : $@convention(thin) (@owned Builtin.NativeObject) -> () {
-bb0(%0 : @owned $Builtin.NativeObject):
-  destroy_value %0 : $Builtin.NativeObject
-  cond_br undef, bb1(%0 : $Builtin.NativeObject), bb2
-
-bb1(%1 : @owned $Builtin.NativeObject):
-  destroy_value %1 : $Builtin.NativeObject
-  br bb2
-
-bb2:
-  %9999 = tuple()
-  return %9999 : $()
-}
-
 /////////////////////////////////////////
 // Movable Guaranteed Scope Test Cases //
 /////////////////////////////////////////