diff options
Diffstat (limited to 'llvm')
| -rw-r--r-- | llvm/lib/CodeGen/MachineBlockPlacement.cpp | 13 | ||||
| -rw-r--r-- | llvm/test/CodeGen/X86/implicit-null-check.ll | 8 |
2 files changed, 17 insertions, 4 deletions
diff --git a/llvm/lib/CodeGen/MachineBlockPlacement.cpp b/llvm/lib/CodeGen/MachineBlockPlacement.cpp index baa9df6c5f1..fb722a166a0 100644 --- a/llvm/lib/CodeGen/MachineBlockPlacement.cpp +++ b/llvm/lib/CodeGen/MachineBlockPlacement.cpp @@ -1358,6 +1358,19 @@ void MachineBlockPlacement::buildCFGChains(MachineFunction &F) { 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) { diff --git a/llvm/test/CodeGen/X86/implicit-null-check.ll b/llvm/test/CodeGen/X86/implicit-null-check.ll index 166408de529..b4c9b5834c8 100644 --- a/llvm/test/CodeGen/X86/implicit-null-check.ll +++ b/llvm/test/CodeGen/X86/implicit-null-check.ll @@ -218,10 +218,10 @@ define i32 @imp_null_check_via_mem_comparision(i32* %x, i32 %val) { ; 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 |
