MachineBasicBlock *TBB = nullptr, *FBB = nullptr; // For AnalyzeBranch.
if (!TII->AnalyzeBranch(F.back(), TBB, FBB, Cond))
F.back().updateTerminator();
+
+ // Now that all the basic blocks in the chain have the proper layout,
+ // make a final call to AnalyzeBranch with AllowModify set.
+ // Indeed, the target may be able to optimize the branches in a way we
+ // cannot because all branches may not be analyzable.
+ // E.g., the target may be able to remove an unconditional branch to
+ // a fallthrough when it occurs after predicated terminators.
+ for (MachineBasicBlock *ChainBB : FunctionChain) {
+ Cond.clear();
+ TBB = nullptr;
+ FBB = nullptr; // For AnalyzeBranch.
+ (void)TII->AnalyzeBranch(*ChainBB, TBB, FBB, Cond, /*AllowModify*/ true);
+ }
}
void MachineBlockPlacement::alignBlocks(MachineFunction &F) {
; OBJDUMP-NEXT: Version: 0x1
; OBJDUMP-NEXT: NumFunctions: 5
; OBJDUMP-NEXT: FunctionAddress: 0x000000, NumFaultingPCs: 1
-; OBJDUMP-NEXT: Fault kind: FaultingLoad, faulting PC offset: 0, handling PC offset: 7
+; OBJDUMP-NEXT: Fault kind: FaultingLoad, faulting PC offset: 0, handling PC offset: 5
; OBJDUMP-NEXT: FunctionAddress: 0x000000, NumFaultingPCs: 1
-; OBJDUMP-NEXT: Fault kind: FaultingLoad, faulting PC offset: 0, handling PC offset: 9
+; OBJDUMP-NEXT: Fault kind: FaultingLoad, faulting PC offset: 0, handling PC offset: 7
; OBJDUMP-NEXT: FunctionAddress: 0x000000, NumFaultingPCs: 1
-; OBJDUMP-NEXT: Fault kind: FaultingLoad, faulting PC offset: 0, handling PC offset: 9
+; OBJDUMP-NEXT: Fault kind: FaultingLoad, faulting PC offset: 0, handling PC offset: 7
; OBJDUMP-NEXT: FunctionAddress: 0x000000, NumFaultingPCs: 1
-; OBJDUMP-NEXT: Fault kind: FaultingLoad, faulting PC offset: 0, handling PC offset: 5
+; OBJDUMP-NEXT: Fault kind: FaultingLoad, faulting PC offset: 0, handling PC offset: 3