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[RISCV] Change the InstFormat for Zicbop prefetch instructions to InstFormatOther.#148934
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…tFormatOther.The lower 5-bits of the immediate are not part of the address unlikeother InstFormatS instructions.We use InstFormatS in RISCVRegisterInfo::needsFrameBaseRegand RISCVRegisterInfo::getFrameIndexInstrOffset which is not aware ofthis special encoding. Force the format to InstFormatOther so thosefunctions will ignore it.InstFormatS is also used by relocation emission, but I don't believewe ever emit these instructions with a relocation because of the encoding.
@llvm/pr-subscribers-backend-risc-v Author: Craig Topper (topperc) ChangesThe lower 5-bits of the immediate are not part of the address unlike other InstFormatS instructions. We use InstFormatS in RISCVRegisterInfo::needsFrameBaseReg and RISCVRegisterInfo::getFrameIndexInstrOffset which is not aware of this special encoding. Force the format to InstFormatOther so those functions will ignore it. InstFormatS is also used by relocation emission, but I don't believe we ever emit these instructions with a relocation because of the encoding. Full diff:https://github.com/llvm/llvm-project/pull/148934.diff 2 Files Affected:
diff --git a/llvm/lib/Target/RISCV/RISCVInstrFormats.td b/llvm/lib/Target/RISCV/RISCVInstrFormats.tdindex b6b64b57b1b3e..e23001a3a0bff 100644--- a/llvm/lib/Target/RISCV/RISCVInstrFormats.td+++ b/llvm/lib/Target/RISCV/RISCVInstrFormats.td@@ -193,7 +193,9 @@ class RVInstCommon<dag outs, dag ins, string opcodestr, string argstr, let AsmString = opcodestr # !if(!empty(argstr), "", "\t" # argstr); let Pattern = pattern;- let TSFlags{4-0} = format.Value;+ InstFormat Format = format;++ let TSFlags{4-0} = Format.Value; // Defaults RISCVVConstraint RVVConstraint = NoConstraint;diff --git a/llvm/lib/Target/RISCV/RISCVInstrInfoZicbo.td b/llvm/lib/Target/RISCV/RISCVInstrInfoZicbo.tdindex 878b85b141578..0723b2f568a79 100644--- a/llvm/lib/Target/RISCV/RISCVInstrInfoZicbo.td+++ b/llvm/lib/Target/RISCV/RISCVInstrInfoZicbo.td@@ -41,6 +41,7 @@ class Prefetch_ri<bits<5> optype, string opcodestr> opcodestr, "${imm12}(${rs1})"> { let Inst{11-7} = 0b00000; let rs2 = optype;+ let Format = InstFormatOther; // this does not follow the normal S format. } //===----------------------------------------------------------------------===// |
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LGTM. Thanks.
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The lower 5-bits of the immediate are not part of the address unlike other InstFormatS instructions.
We use InstFormatS in RISCVRegisterInfo::needsFrameBaseReg and RISCVRegisterInfo::getFrameIndexInstrOffset which is not aware of this special encoding. Force the format to InstFormatOther so those functions will ignore it.
InstFormatS is also used by relocation emission, but I don't believe we ever emit these instructions with a relocation because of the encoding.