From bae6d527dffbe302a8130ceb40b4e82cf61414b1 Mon Sep 17 00:00:00 2001 From: David Majnemer Date: Thu, 11 Apr 2013 20:13:52 +0000 Subject: [PATCH] Fix undefined behavior in AArch64 A64Imms::isLogicalImmBits and A64Imms::isLogicalImm will attempt to execute shifts that perform undefined behavior. Instead of attempting to perform the 64-bit rotation, treat it as a no-op. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179317 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Target/AArch64/Utils/AArch64BaseInfo.cpp | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) diff --git a/lib/Target/AArch64/Utils/AArch64BaseInfo.cpp b/lib/Target/AArch64/Utils/AArch64BaseInfo.cpp index 1678559aa08..bedccb5438f 100644 --- a/lib/Target/AArch64/Utils/AArch64BaseInfo.cpp +++ b/lib/Target/AArch64/Utils/AArch64BaseInfo.cpp @@ -981,8 +981,11 @@ bool A64Imms::isLogicalImm(unsigned RegWidth, uint64_t Imm, uint32_t &Bits) { Rotation = RepeatWidth - Rotation; } - uint64_t ReplicatedOnes = (ReplicatedMask >> Rotation) - | ((ReplicatedMask << (RepeatWidth - Rotation)) & RepeatMask); + uint64_t ReplicatedOnes = ReplicatedMask; + if (Rotation != 0 && Rotation != 64) + ReplicatedOnes = (ReplicatedMask >> Rotation) + | ((ReplicatedMask << (RepeatWidth - Rotation)) & RepeatMask); + // Of course, they may not actually be ones, so we have to check that: if (!isMask_64(ReplicatedOnes)) continue; @@ -1051,13 +1054,14 @@ bool A64Imms::isLogicalImmBits(unsigned RegWidth, uint32_t Bits, int Rotation = (ImmR & (Width - 1)); uint64_t Mask = (1ULL << Num1s) - 1; uint64_t WidthMask = Width == 64 ? -1 : (1ULL << Width) - 1; - Mask = (Mask >> Rotation) - | ((Mask << (Width - Rotation)) & WidthMask); + if (Rotation != 0 && Rotation != 64) + Mask = (Mask >> Rotation) + | ((Mask << (Width - Rotation)) & WidthMask); - Imm = 0; - for (unsigned i = 0; i < RegWidth / Width; ++i) { - Imm |= Mask; + Imm = Mask; + for (unsigned i = 1; i < RegWidth / Width; ++i) { Mask <<= Width; + Imm |= Mask; } return true; -- 2.34.1