From 373f9a6a0c95fcdb6ee99eea8450d3cb546921a7 Mon Sep 17 00:00:00 2001 From: Daniel Jasper Date: Sun, 18 Dec 2016 14:36:38 +0000 Subject: Revert r289955 and r289962. This is causing lots of ASAN failures for us. Not sure whether it causes and ASAN false positive or whether it actually leads to incorrect code or whether it even exposes bad code. Hans, I'll get you instructions to reproduce this. llvm-svn: 290066 --- llvm/lib/Target/X86/X86ISelLowering.cpp | 32 ++++++++++---------------------- 1 file changed, 10 insertions(+), 22 deletions(-) (limited to 'llvm/lib') diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp index e29c7cd6e3b..1470952f176 100644 --- a/llvm/lib/Target/X86/X86ISelLowering.cpp +++ b/llvm/lib/Target/X86/X86ISelLowering.cpp @@ -28985,19 +28985,11 @@ static SDValue combineSelect(SDNode *N, SelectionDAG &DAG, return SDValue(); } -/// Combine brcond/cmov/setcc/.. based on comparing the result of -/// atomic_load_add to use EFLAGS produced by the addition -/// directly if possible. For example: -/// -/// (setcc (cmp (atomic_load_add x, -C) C), COND_E) -/// becomes: -/// (setcc (LADD x, -C), COND_E) -/// -/// and +/// Combine: /// (brcond/cmov/setcc .., (cmp (atomic_load_add x, 1), 0), COND_S) -/// becomes: +/// to: /// (brcond/cmov/setcc .., (LADD x, 1), COND_LE) -/// +/// i.e., reusing the EFLAGS produced by the LOCKed instruction. /// Note that this is only legal for some op/cc combinations. static SDValue combineSetCCAtomicArith(SDValue Cmp, X86::CondCode &CC, SelectionDAG &DAG) { @@ -29006,7 +28998,7 @@ static SDValue combineSetCCAtomicArith(SDValue Cmp, X86::CondCode &CC, (Cmp.getOpcode() == X86ISD::SUB && !Cmp->hasAnyUseOfValue(0)))) return SDValue(); - // This applies to variations of the common case: + // This only applies to variations of the common case: // (icmp slt x, 0) -> (icmp sle (add x, 1), 0) // (icmp sge x, 0) -> (icmp sgt (add x, 1), 0) // (icmp sle x, 0) -> (icmp slt (sub x, 1), 0) @@ -29025,9 +29017,8 @@ static SDValue combineSetCCAtomicArith(SDValue Cmp, X86::CondCode &CC, return SDValue(); auto *CmpRHSC = dyn_cast(CmpRHS); - if (!CmpRHSC) + if (!CmpRHSC || CmpRHSC->getZExtValue() != 0) return SDValue(); - APInt Comparand = CmpRHSC->getAPIntValue(); const unsigned Opc = CmpLHS.getOpcode(); @@ -29043,19 +29034,16 @@ static SDValue combineSetCCAtomicArith(SDValue Cmp, X86::CondCode &CC, if (Opc == ISD::ATOMIC_LOAD_SUB) Addend = -Addend; - if (Comparand == -Addend) { - // No change to CC. - } else if (CC == X86::COND_S && Comparand == 0 && Addend == 1) { + if (CC == X86::COND_S && Addend == 1) CC = X86::COND_LE; - } else if (CC == X86::COND_NS && Comparand == 0 && Addend == 1) { + else if (CC == X86::COND_NS && Addend == 1) CC = X86::COND_G; - } else if (CC == X86::COND_G && Comparand == 0 && Addend == -1) { + else if (CC == X86::COND_G && Addend == -1) CC = X86::COND_GE; - } else if (CC == X86::COND_LE && Comparand == 0 && Addend == -1) { + else if (CC == X86::COND_LE && Addend == -1) CC = X86::COND_L; - } else { + else return SDValue(); - } SDValue LockOp = lowerAtomicArithWithLOCK(CmpLHS, DAG); DAG.ReplaceAllUsesOfValueWith(CmpLHS.getValue(0), -- cgit v1.2.3