JIT: Small primitives on arm32/apple arm64 ABI need explicit normalization to 32 bits #101046
Description
ARM32 and Apple ARM64 ABIs both require normalization up to 32 bits for primitives. For example, a ushort must always be zero extended to 32 bits and short must always be sign extended.
The JIT does not explicitly insert this normalization anywhere. The following example using inline IL shows bad codegen on arm32 and apple arm64 because of it:
[MethodImpl(MethodImplOptions.NoInlining)]
public static void Foo(delegate*<short, int> test, ref ushort p)
{
IL.Push(p);
IL.Push(test);
IL.Emit.Calli(new StandAloneMethodSig(System.Runtime.InteropServices.CallingConvention.Cdecl, typeof(int), typeof(short)));
IL.Pop(out int value);
}arm32 codegen:
G_M18803_IG02: ;; offset=0x000E
00000E add r4, sp, 4
000010 movw r3, 0x33f4
000014 movt r3, 0x2f3
000018 blx r3 // CORINFO_HELP_INIT_PINVOKE_FRAME
00001A ldrh r0, [r7] ; needs additional sign extension
00001C movs r3, 0
00001E str r3, [sp+0x0C]
000020 movw r3, LOW ADDRESS G_M18803_IG04
000024 movt r3, HIGH ADDRESS G_M18803_IG04
000028 str r3, [sp+0x14]
00002A movs r3, 0
00002C strb r3, [r5+0x04]
;; size=32 bbWeight=1 PerfScore 12.00
G_M18803_IG03: ;; offset=0x002E
00002E blx r8apple arm64 codegen:
G_M49066_IG02: ;; offset=0x0024
add x0, fp, #32 // [V05 PInvokeFrame+0x08]
mov x1, xzr
bl CORINFO_HELP_INIT_PINVOKE_FRAME
mov x21, x0
mov x0, sp
str x0, [fp, #0x40] // [V05 PInvokeFrame+0x28]
mov x0, fp
str x0, [fp, #0x50] // [V05 PInvokeFrame+0x38]
ldrh w0, [x19] ; needs additional sign extension
adr x1, [G_M49066_IG04]
str x1, [fp, #0x48] // [V05 PInvokeFrame+0x30]
add x1, fp, #32 // [V05 PInvokeFrame+0x08]
str x1, [x21, #0x08]
strb wzr, [x21, #0x04]
;; size=56 bbWeight=1 PerfScore 12.50
G_M49066_IG03: ;; offset=0x005C
blr x20This issue is probably not reproducible in IL created from C# since the JIT generally keeps values zero/sign extended to 32 bits.