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Summary: Previously SelectionDAGBuilder asserted that the pointer operands of memcpy / memset / memmove intrinsics are in address space < 256. This assert implicitly assumed the X86 backend, where all address spaces < 256 are equivalent to address space 0 from the code generator's point of view. On some targets (R600 and NVPTX) several address spaces < 256 have a target-defined meaning, so this assert made little sense for these targets. This patch removes this wrong assertion and adds extra checks before lowering these intrinsics to library calls. If a pointer operand can't be casted to address space 0 without changing semantics, a fatal error is reported to the user. The new behavior should be valid for all targets that give address spaces != 0 a target-specified meaning (NVPTX, R600, X86). NVPTX lowers big or variable-sized memory intrinsics before SelectionDAG construction. All other memory intrinsics are inlined (the threshold is set very high for this target). R600 doesn't support memcpy / memset / memmove library calls (previously the illegal emission of a call to such library function triggered an error somewhere in the code generator). X86 now emits inline loads and stores for address spaces 256 and 257 up to the same threshold that is used for address space 0 and reports a fatal error otherwise. I call this a "partial fix" because there are still cases that can't be lowered. A fatal error is reported in these cases. Reviewers: arsenm, theraven, compnerd, hfinkel Subscribers: hfinkel, llvm-commits, alex Differential Revision: http://reviews.llvm.org/D7241 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@255441 91177308-0d34-0410-b5e6-96231b3b80d8
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