[compiler-rt] [compiler-rt][ARM] Optimized mulsf3 and divsf3 (PR #161546)

[Saleem Abdulrasool via llvm-commits]

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@@ -422,6 +422,24 @@ set(arm_or_thumb2_base_SOURCES
   ${GENERIC_SOURCES}
 )
 
+option(COMPILER_RT_ARM_OPTIMIZED_FP
+  "On 32-bit Arm, use optimized assembly implementations of FP arithmetic. Likely to increase code size, but be faster." ON)
+
+if(COMPILER_RT_ARM_OPTIMIZED_FP)
+  set(assembly_files
+    arm/mulsf3.S
+    arm/divsf3.S)
+  set_source_files_properties(${assembly_files}
+    PROPERTIES COMPILE_OPTIONS "-Wa,-mimplicit-it=always")
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compnerd wrote:

Might be nice to limit this to when the driver supports it. This is important if the build is using the raw assembler vs the compiler driver (i.e. `-implicit-it=always` vs -Xa `-implicit-it=always`)

https://github.com/llvm/llvm-project/pull/161546