)]}'
{
  "commit": "6adef02db58873b1ef5cd2fac967bf1072567751",
  "tree": "d095e93c0d09baeea160c47d885d501f994e96ff",
  "parents": [
    "94d9d9c76201058378a8a74f49b7b057f695ccc4"
  ],
  "author": {
    "name": "Henry Baba-Weiss",
    "email": "henry.babaweiss@gmail.com",
    "time": "Mon Apr 13 13:03:39 2026 -0700"
  },
  "committer": {
    "name": "GitHub",
    "email": "noreply@github.com",
    "time": "Mon Apr 13 13:03:39 2026 -0700"
  },
  "message": "[X86][regcall] Rework struct classification for non-Windows x86-64 targets (#187134)\n\nCurrently, when `X86_64ABIInfo::classifyRegCallStructTypeImpl`\nclassifies a struct argument or return value as direct, it leaves the\nLLVM IR coerce type unspecified, implicitly relying on\n`CodeGenTypes::ConvertType` to eventually construct a default IR type\nbased on the struct\u0027s layout. This conversion is neither stable nor\nguaranteed to adhere to the ABI\u0027s classification rules.\n\nInstead, rewrite `classifyRegCallStructTypeImpl` to construct an\nexplicit sequence of coerce types, using the existing field\nclassification to obtain a coerce type for each member of the struct.\nAlso, rename the function to `passRegCallStructTypeDirectly` and return\na boolean instead, so that now `classifyRegCallStructType` is the only\nplace that computes `ABIArgInfo`.\n\nThis rewrite also fixes several other issues with the `X86_64ABIInfo`\nimplementation of `__regcall`:\n\n* Empty structs are now ignored instead of being misclassified as\ndirect.\n* Arrays are now classified specially based on the element type, since\n`X86_64ABIInfo::classifyArgumentType` ignores standalone array types.\n* SSE registers used for return values are now correctly reused for\narguments, matching the 64-bit Windows behavior.\n\nSince this is an ABI change, it has the potential to cause\nincompatibilities with `__regcall` code compiled by earlier versions of\nClang. Specifically:\n\n* Because SSE return registers can now be reused as argument registers,\nfunctions will now pass more floating point arguments in SSE registers.\n* `_Complex float` struct fields are now passed in one SSE register\ninstead of two.\n\nFixes #62999\nFixes #98635",
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