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LLVM backend for 6502
4d962b05ca
Currently, @llvm.smul.with.overflow.i8 expands to 9 instructions, where 3 are really needed. This adds X86ISD::UMUL8/SMUL8 SD nodes, and custom lowers them to MUL8/IMUL8 + SETO. i8 is a special case because there is no two/three operand variants of (I)MUL8, so the first operand and return value need to go in AL/AX. Also, we can't write patterns for these instructions: TableGen refuses patterns where output operands don't match SDNode results. In this case, instructions where the output operand is an implicitly defined register. A related special case (and FIXME) exists for MUL8 (X86InstrArith.td): // FIXME: Used for 8-bit mul, ignore result upper 8 bits. // This probably ought to be moved to a def : Pat<> if the // syntax can be accepted. [(set AL, (mul AL, GR8:$src)), (implicit EFLAGS)] Ideally, these go away with UMUL8, but we still need to improve TableGen support of implicit operands in patterns. Before this change: movsbl %sil, %eax movsbl %dil, %ecx imull %eax, %ecx movb %cl, %al sarb $7, %al movzbl %al, %eax movzbl %ch, %esi cmpl %eax, %esi setne %al After: movb %dil, %al imulb %sil seto %al Also, remove a made-redundant testcase for PR19858, and enable more FastISel ALU-overflow tests for SelectionDAG too. Differential Revision: http://reviews.llvm.org/D5809 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220516 91177308-0d34-0410-b5e6-96231b3b80d8 |
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| lib | ||
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| unittests | ||
| utils | ||
| .arcconfig | ||
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| .gitignore | ||
| CMakeLists.txt | ||
| CODE_OWNERS.TXT | ||
| configure | ||
| CREDITS.TXT | ||
| LICENSE.TXT | ||
| llvm.spec.in | ||
| LLVMBuild.txt | ||
| Makefile | ||
| Makefile.common | ||
| Makefile.config.in | ||
| Makefile.rules | ||
| README.txt | ||
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