From 01b593fc4e53480868b2ae97bc65a88b6184c4d9 Mon Sep 17 00:00:00 2001 From: Josh Stone Date: Tue, 18 Apr 2017 15:24:58 -0700 Subject: [PATCH] Fix computeKnownBits for ARMISD::CMOV (rust-lang/llvm#67) --- llvm.spec | 9 ++++- rust-lang-llvm-pr67.patch | 70 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 78 insertions(+), 1 deletion(-) create mode 100644 rust-lang-llvm-pr67.patch diff --git a/llvm.spec b/llvm.spec index 6e62d02..6630249 100644 --- a/llvm.spec +++ b/llvm.spec @@ -7,7 +7,7 @@ Name: llvm Version: 3.8.1 -Release: 2%{?dist} +Release: 3%{?dist} Summary: The Low Level Virtual Machine License: NCSA @@ -22,6 +22,9 @@ Patch0: llvm-3.7.1-cmake-s390.patch # backport D18644 [SystemZ] Support ATOMIC_FENCE Patch1: llvm-d18644-systemz-atomic-fence.patch +# backports cribbed from https://github.com/rust-lang/llvm/ +Patch67: rust-lang-llvm-pr67.patch + BuildRequires: cmake BuildRequires: zlib-devel BuildRequires: libffi-devel @@ -74,6 +77,7 @@ Static libraries for the LLVM compiler infrastructure. %setup -q -n %{name}-%{version}.src %patch0 -p1 -b .s390 %patch1 -p2 -b .s390-fence +%patch67 -p1 -b .rust67 %build mkdir -p _build @@ -190,6 +194,9 @@ make check-all || : %{_libdir}/*.a %changelog +* Tue Apr 18 2017 Josh Stone - 3.8.1-3 +- Fix computeKnownBits for ARMISD::CMOV (rust-lang/llvm#67) + * Sat Jan 07 2017 Josh Stone - 3.8.1-2 - Support s390x atomic fence diff --git a/rust-lang-llvm-pr67.patch b/rust-lang-llvm-pr67.patch new file mode 100644 index 0000000..3edbde9 --- /dev/null +++ b/rust-lang-llvm-pr67.patch @@ -0,0 +1,70 @@ +From a6fa10c14649c18d299cddf3e823b032460cb6f5 Mon Sep 17 00:00:00 2001 +From: Pirama Arumuga Nainar +Date: Thu, 23 Mar 2017 16:47:47 +0000 +Subject: [PATCH] Fix computeKnownBits for ARMISD::CMOV + +Summary: +The true and false operands for the CMOV are operands 0 and 1. +ARMISelLowering.cpp::computeKnownBits was looking at operands 1 and 2 +instead. This can cause CMOV instructions to be incorrectly folded into +BFI if value set by the CMOV is another CMOV, whose known bits are +computed incorrectly. + +This patch fixes the issue and adds a test case. + +Reviewers: kristof.beyls, jmolloy + +Subscribers: llvm-commits, aemerson, srhines, rengolin + +Differential Revision: https://reviews.llvm.org/D31265 + +git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@298624 91177308-0d34-0410-b5e6-96231b3b80d8 +--- + lib/Target/ARM/ARMISelLowering.cpp | 4 ++-- + test/CodeGen/ARM/no-cmov2bfi.ll | 19 +++++++++++++++++++ + 2 files changed, 21 insertions(+), 2 deletions(-) + create mode 100644 test/CodeGen/ARM/no-cmov2bfi.ll + +diff --git a/lib/Target/ARM/ARMISelLowering.cpp b/lib/Target/ARM/ARMISelLowering.cpp +index 4a227a3cd7b1..cf98e60c0657 100644 +--- a/lib/Target/ARM/ARMISelLowering.cpp ++++ b/lib/Target/ARM/ARMISelLowering.cpp +@@ -10806,8 +10806,8 @@ static void computeKnownBits(SelectionDAG &DAG, SDValue Op, APInt &KnownZero, + if (Op.getOpcode() == ARMISD::CMOV) { + APInt KZ2(KnownZero.getBitWidth(), 0); + APInt KO2(KnownOne.getBitWidth(), 0); +- computeKnownBits(DAG, Op.getOperand(1), KnownZero, KnownOne); +- computeKnownBits(DAG, Op.getOperand(2), KZ2, KO2); ++ computeKnownBits(DAG, Op.getOperand(0), KnownZero, KnownOne); ++ computeKnownBits(DAG, Op.getOperand(1), KZ2, KO2); + + KnownZero &= KZ2; + KnownOne &= KO2; +diff --git a/test/CodeGen/ARM/no-cmov2bfi.ll b/test/CodeGen/ARM/no-cmov2bfi.ll +new file mode 100644 +index 000000000000..c8b512048905 +--- /dev/null ++++ b/test/CodeGen/ARM/no-cmov2bfi.ll +@@ -0,0 +1,19 @@ ++; RUN: llc < %s -mtriple=thumbv7 | FileCheck --check-prefix=CHECK-NOBFI %s ++ ++declare zeroext i1 @dummy() ++ ++define i8 @test(i8 %a1, i1 %c) { ++; CHECK-NOBFI-NOT: bfi ++; CHECK-NOBFI: bl dummy ++; CHECK-NOBFI: cmp r0, #0 ++; CHECK-NOBFI: it ne ++; CHECK-NOBFI: orrne [[REG:r[0-9]+]], [[REG]], #8 ++; CHECK-NOBFI: mov r0, [[REG]] ++ ++ %1 = and i8 %a1, -9 ++ %2 = select i1 %c, i8 %1, i8 %a1 ++ %3 = tail call zeroext i1 @dummy() ++ %4 = or i8 %2, 8 ++ %ret = select i1 %3, i8 %4, i8 %2 ++ ret i8 %ret ++} +-- +2.9.3 +