[AArch64] Return early rather than asserting when Size of value passed to targetShrinkDemandedConstant is not 32 or 64

Author: WillFroom

llvm/lib/Target/AArch64/AArch64ISelLowering.cpp

@@ -2373,8 +2373,9 @@ bool AArch64TargetLowering::targetShrinkDemandedConstant(
     return false;
 
   unsigned Size = VT.getSizeInBits();
-  assert((Size == 32 || Size == 64) &&
-         "i32 or i64 is expected after legalization.");
+
+  if (Size != 32 && Size != 64)
+    return false;
 
   // Exit early if we demand all bits.
   if (DemandedBits.popcount() == Size)

llvm/test/CodeGen/AArch64/half-presision-signof-no-assert.ll

@@ -0,0 +1,22 @@
+; RUN: llc -o - %s
+
+; Simply check that the following does not crash (see https://github.com/llvm/llvm-project/issues/123029)
+
+target triple = "aarch64-unknown-linux-gnu"
+
+define noalias noundef ptr @fn(ptr nocapture readonly %in, ptr nocapture readonly %out) local_unnamed_addr {
+fn:
+  %1 = load <4 x half>, ptr %in, align 16
+  %2 = fcmp one <4 x half> %1, zeroinitializer
+  %3 = uitofp <4 x i1> %2 to <4 x half>
+  store <4 x half> %3, ptr %out, align 16
+
+  %23 = getelementptr inbounds nuw i8, ptr %in, i64 8
+  %24 = load half, ptr %23, align 4
+  %25 = fcmp one half %24, 0xH0000
+  %26 = uitofp i1 %25 to half
+  %27 = call half @llvm.copysign.f16(half %26, half %24)
+  %30 = getelementptr inbounds nuw i8, ptr %out, i64 8
+  store half %27, ptr %30, align 8
+  ret ptr null
+}