Replace an assertion with a fatal error

Frontends are responsible for putting inalloca on parameters that would
be passed in memory and not registers.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213891 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/X86/X86ISelLowering.cpp

@@ -2680,8 +2680,12 @@ X86TargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
   // arguments passed in memory when using inalloca.
   if (!Outs.empty() && Outs.back().Flags.isInAlloca()) {
     NumBytesToPush = 0;
-    assert(ArgLocs.back().getLocMemOffset() == 0 &&
-           "an inalloca argument must be the only memory argument");
+    if (!ArgLocs.back().isMemLoc())
+      report_fatal_error("cannot use inalloca attribute on a register "
+                         "parameter");
+    if (ArgLocs.back().getLocMemOffset() != 0)
+      report_fatal_error("any parameter with the inalloca attribute must be "
+                         "the only memory argument");
   }
 
   if (!IsSibcall)

test/CodeGen/X86/inalloca-regparm.ll

@@ -0,0 +1,15 @@
+; RUN: llc -mtriple=i686-windows-msvc < %s -o /dev/null
+; RUN: not llc -mtriple=x86_64-windows-msvc %s -o /dev/null 2>&1 | FileCheck %s
+
+; This will compile successfully on x86 but not x86_64, because %b will become a
+; register parameter.
+
+declare x86_thiscallcc i32 @f(i32 %a, i32* inalloca %b)
+define void @g() {
+  %b = alloca inalloca i32
+  store i32 2, i32* %b
+  call x86_thiscallcc i32 @f(i32 0, i32* inalloca %b)
+  ret void
+}
+
+; CHECK: cannot use inalloca attribute on a register parameter