[AArch64] Return early rather than asserting when Size of value passed to targetShrinkDemandedConstant is not 32 or 64 (#123084)

See #123029 for details.

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-precision-signof-no-assert.ll

@@ -0,0 +1,48 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
+; RUN: llc --mtriple=aarch64-unknown-linux-gnu < %s | FileCheck %s
+
+; Check that the following does not crash
+; See https://github.com/llvm/llvm-project/issues/123029 for details
+
+define ptr @fn(ptr %in, ptr %out) {
+; CHECK-LABEL: fn:
+; CHECK:       // %bb.0: // %fn
+; CHECK-NEXT:    ldr d1, [x0]
+; CHECK-NEXT:    movi v0.4h, #60, lsl #8
+; CHECK-NEXT:    adrp x8, .LCPI0_0
+; CHECK-NEXT:    fcvtl v1.4s, v1.4h
+; CHECK-NEXT:    fcmgt v2.4s, v1.4s, #0.0
+; CHECK-NEXT:    fcmlt v1.4s, v1.4s, #0.0
+; CHECK-NEXT:    orr v1.16b, v1.16b, v2.16b
+; CHECK-NEXT:    ldr h2, [x8, :lo12:.LCPI0_0]
+; CHECK-NEXT:    xtn v1.4h, v1.4s
+; CHECK-NEXT:    and v0.8b, v1.8b, v0.8b
+; CHECK-NEXT:    movi d1, #0000000000000000
+; CHECK-NEXT:    str d0, [x1]
+; CHECK-NEXT:    ldr h0, [x0, #8]
+; CHECK-NEXT:    mov x0, xzr
+; CHECK-NEXT:    fcvt s0, h0
+; CHECK-NEXT:    fcmp s0, #0.0
+; CHECK-NEXT:    fcsel s1, s2, s1, mi
+; CHECK-NEXT:    fcsel s1, s2, s1, gt
+; CHECK-NEXT:    mvni v2.4s, #128, lsl #24
+; CHECK-NEXT:    fcvt s1, h1
+; CHECK-NEXT:    bit v0.16b, v1.16b, v2.16b
+; CHECK-NEXT:    fcvt h0, s0
+; CHECK-NEXT:    str h0, [x1, #8]
+; CHECK-NEXT:    ret
+fn:
+  %1 = load <4 x half>, ptr %in
+  %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
+
+  %4 = getelementptr inbounds nuw i8, ptr %in, i64 8
+  %5 = load half, ptr %4
+  %6 = fcmp one half %5, 0xH0000
+  %7 = uitofp i1 %6 to half
+  %8 = call half @llvm.copysign.f16(half %7, half %5)
+  %9 = getelementptr inbounds nuw i8, ptr %out, i64 8
+  store half %8, ptr %9
+  ret ptr null
+}