reapply "[TargetInstrInfo] enable foldMemoryOperand for InlineAsm (#70743)" #72910
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nickdesaulniers
referenced
this pull request
Nov 20, 2023
foldMemoryOperand looks at pairs of instructions (generally a load to virt reg then use of the virtreg, or def of a virtreg then a store) and attempts to combine them. This can reduce register pressure. A prior commit added the ability to mark such a MachineOperand as foldable. In terms of INLINEASM, this means that "rm" was used (rather than just "r") to denote that the INLINEASM may use a memory operand rather than a register operand. This effectively undoes decisions made by the instruction selection framework. Callers will be added in the register allocation frameworks. This has been tested with all of the above (which will come as follow up patches). Thanks to @topperc who suggested this at last years LLVM US Dev Meeting and @qcolombet who confirmed this was the right approach. Link: #20571
bwendling
approved these changes
Nov 20, 2023
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This reverts commit 42204c9.
It was accidentally backed out.
#20571
#70743