[llvm] [X86] Resolve FIXME: Add FPCW as a rounding control register (PR #82452)

[Shengchen Kan via llvm-commits]

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@@ -3443,6 +3443,8 @@ static bool isX87Reg(unsigned Reg) {
 
 /// check if the instruction is X87 instruction
 bool X86::isX87Instruction(MachineInstr &MI) {
+  if (MI.isCall())
+    return false;
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KanRobert wrote:

Could you add comment to explain this, e.g. ".Call defs X87 register but should not be classified as X87 instruction."?

https://github.com/llvm/llvm-project/pull/82452