[llvm] [AArch64][CodeGen] Fix crash when fptrunc returns fp16 with +nofp attr (PR #81724)

[via llvm-commits]

================
@@ -0,0 +1,21 @@
+; RUN: llc -mcpu=cortex-r82 -O1 -o - %s | FileCheck %s
+
+; Source used:
+; __fp16 f2h(float a) { return a; }
+; Compiled with: clang --target=aarch64-arm-none-eabi -march=armv8-r+nofp
+
+define hidden noundef nofpclass(nan inf) half @f2h(float noundef nofpclass(nan inf) %a) local_unnamed_addr #0 {
+;CHECK:      f2h:                                    // @f2h
+;CHECK-NEXT: // %bb.0:                               // %entry
+;CHECK-NEXT:     str x30, [sp, #-16]!                // 8-byte Folded Spill
+;CHECK-NEXT:     bl  __gnu_h2f_ieee
----------------
ostannard wrote:

This is the wrong library call, the IR input is doing a a `float->half` conversion, but the generated assembly is for a `half->float` conversion.

https://github.com/llvm/llvm-project/pull/81724