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author | Matheus Almeida <matheus.almeida@imgtec.com> | 2014-06-18 14:49:56 +0000 |
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committer | Matheus Almeida <matheus.almeida@imgtec.com> | 2014-06-18 14:49:56 +0000 |
commit | c39b18b306c7681cb155127096a56afbea24a08e (patch) | |
tree | 7bba92c9087b4361a3e8556f8815b02a87965a5d /lib/Target/Mips | |
parent | cacc0625726e9fba539201543a770b4795c22792 (diff) | |
download | llvm-c39b18b306c7681cb155127096a56afbea24a08e.tar.gz llvm-c39b18b306c7681cb155127096a56afbea24a08e.tar.bz2 llvm-c39b18b306c7681cb155127096a56afbea24a08e.tar.xz |
[mips] Fix expansion of memory operation if destination register is not a GPR.
Summary:
The assembler tries to reuse the destination register for memory operations whenever
it can but it's not possible to do so if the destination register is not a GPR.
Example:
ldc1 $f0, sym
should expand to:
lui $at, %hi(sym)
ldc1 $f0, %lo(sym)($at)
It's entirely wrong to expand to:
lui $f0, %hi(sym)
ldc1 $f0, %lo(sym)($f0)
Reviewers: dsanders
Reviewed By: dsanders
Differential Revision: http://reviews.llvm.org/D4173
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211169 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Target/Mips')
-rw-r--r-- | lib/Target/Mips/AsmParser/MipsAsmParser.cpp | 33 |
1 files changed, 29 insertions, 4 deletions
diff --git a/lib/Target/Mips/AsmParser/MipsAsmParser.cpp b/lib/Target/Mips/AsmParser/MipsAsmParser.cpp index 4a226a9f9d..dd2b857789 100644 --- a/lib/Target/Mips/AsmParser/MipsAsmParser.cpp +++ b/lib/Target/Mips/AsmParser/MipsAsmParser.cpp @@ -1144,10 +1144,35 @@ void MipsAsmParser::expandMemInst(MCInst &Inst, SMLoc IDLoc, ExprOffset = Inst.getOperand(2).getExpr(); // All instructions will have the same location. TempInst.setLoc(IDLoc); - // 1st instruction in expansion is LUi. For load instruction we can use - // the dst register as a temporary if base and dst are different, - // but for stores we must use $at. - if (isLoad && (BaseRegNum != RegOpNum)) + // These are some of the types of expansions we perform here: + // 1) lw $8, sym => lui $8, %hi(sym) + // lw $8, %lo(sym)($8) + // 2) lw $8, offset($9) => lui $8, %hi(offset) + // add $8, $8, $9 + // lw $8, %lo(offset)($9) + // 3) lw $8, offset($8) => lui $at, %hi(offset) + // add $at, $at, $8 + // lw $8, %lo(offset)($at) + // 4) sw $8, sym => lui $at, %hi(sym) + // sw $8, %lo(sym)($at) + // 5) sw $8, offset($8) => lui $at, %hi(offset) + // add $at, $at, $8 + // sw $8, %lo(offset)($at) + // 6) ldc1 $f0, sym => lui $at, %hi(sym) + // ldc1 $f0, %lo(sym)($at) + // + // For load instructions we can use the destination register as a temporary + // if base and dst are different (examples 1 and 2) and if the base register + // is general purpose otherwise we must use $at (example 6) and error if it's + // not available. For stores we must use $at (examples 4 and 5) because we + // must not clobber the source register setting up the offset. + const MCInstrDesc &Desc = getInstDesc(Inst.getOpcode()); + int16_t RegClassOp0 = Desc.OpInfo[0].RegClass; + unsigned RegClassIDOp0 = + getContext().getRegisterInfo()->getRegClass(RegClassOp0).getID(); + bool IsGPR = (RegClassIDOp0 == Mips::GPR32RegClassID) || + (RegClassIDOp0 == Mips::GPR64RegClassID); + if (isLoad && IsGPR && (BaseRegNum != RegOpNum)) TmpRegNum = RegOpNum; else { int AT = getATReg(IDLoc); |