[AArch64][GlobalISel] Don't try to use GISel if subtarget doesn't hav…

…e neon or fp.

Throughout the legalizerinfo we currently make the assumption that the target
has neon and FP target features available. Fixing it will require a refactor of
the whole thing, so until then make sure we fall back.

Works around PR42734

Differential Revision: https://reviews.llvm.org/D65244

llvm-svn: 366957

llvm/lib/Target/AArch64/AArch64LegalizerInfo.cpp

@@ -52,6 +52,12 @@ AArch64LegalizerInfo::AArch64LegalizerInfo(const AArch64Subtarget &ST) {
   const LLT v2s64 = LLT::vector(2, 64);
   const LLT v2p0 = LLT::vector(2, p0);
 
+  // FIXME: support subtargets which have neon/fp-armv8 disabled.
+  if (!ST.hasNEON() || !ST.hasFPARMv8()) {
+    computeTables();
+    return;
+  }
+
   getActionDefinitionsBuilder(G_IMPLICIT_DEF)
     .legalFor({p0, s1, s8, s16, s32, s64, v4s32, v2s64})
     .clampScalar(0, s1, s64)

llvm/test/CodeGen/AArch64/GlobalISel/no-neon-no-fp.ll

@@ -0,0 +1,13 @@
+; RUN: not llc -o - -verify-machineinstrs -global-isel -global-isel-abort=1 -stop-after=legalizer %s 2>&1 | FileCheck %s
+target datalayout = "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128"
+target triple = "aarch64-unknown-unknown"
+
+; CHECK: unable to legalize instruction: G_STORE %1:_(s128), %0:_(p0) :: (store 16 into %ir.ptr) (in function: foo)
+define void @foo(i128 *%ptr) #0 align 2 {
+entry:
+  store i128 0, i128* %ptr, align 16
+  ret void
+}
+
+attributes #0 = { "use-soft-float"="false" "target-features"="-fp-armv8,-neon" }
+