Index: llvm/lib/CodeGen/IfConversion.cpp =================================================================== --- llvm/lib/CodeGen/IfConversion.cpp +++ llvm/lib/CodeGen/IfConversion.cpp @@ -972,6 +972,11 @@ FalseBBI.IsBeingAnalyzed || FalseBBI.IsDone) return false; + // If the True and False BBs are equal we're dealing with a degenerate case + // that we don't treat as a diamond. + if (TrueBBI.BB == FalseBBI.BB) + return false; + MachineBasicBlock *TT = TrueBBI.TrueBB; MachineBasicBlock *FT = FalseBBI.TrueBB; Index: llvm/test/CodeGen/ARM/ifcvt_diamondSameTrueFalse.mir =================================================================== --- /dev/null +++ llvm/test/CodeGen/ARM/ifcvt_diamondSameTrueFalse.mir @@ -0,0 +1,40 @@ +# RUN: llc -mtriple=thumbv7-apple-ios -o - %s -run-pass if-converter -verify-machineinstrs | FileCheck %s + +# Don't treat bb.1 as a valid diamond since IfConverter::IfConvertDiamond can't +# handle it and used to hit an assertion instead. + +--- | + define void @func() minsize { + ret void + } +... +--- +name: func +body: | + bb.0: + + tBcc %bb.3, 1, $cpsr + + bb.1: + + tBcc %bb.2, 1, $cpsr + tB %bb.2, 14, $noreg + + bb.2: + + bb.3: + successors: + tBX_RET 14, _ +... + +# CHECK-LABEL: bb.0: +# CHECK: tBcc %bb.3, 1 + +# CHECK-LABEL: bb.1: +# CHECK: tBcc %bb.2, 1 +# CHECK-NEXT: tB %bb.2, 14 + +# CHECK-LABEL: bb.2: + +# CHECK-LABEL: bb.3: +# CHECK: tBX_RET 14