[llvm] r296754 - GlobalISel: record correct stack usage for signext parameters.

[Tim Northover via llvm-commits]

Author: tnorthover
Date: Thu Mar  2 09:34:18 2017
New Revision: 296754

URL: http://llvm.org/viewvc/llvm-project?rev=296754&view=rev
Log:
GlobalISel: record correct stack usage for signext parameters.

The CallingConv.td rules allocate 8 bytes for these kinds of arguments
on AAPCS targets, but we were only recording the smaller amount. The
difference is theoretical on AArch64 because we don't actually store
more than the smaller amount, but it's still much better to have these
two components in agreement.

Based on Diana Picus's ARM equivalent patch (where it matters a lot
more).

Modified:
    llvm/trunk/lib/Target/AArch64/AArch64CallLowering.cpp
    llvm/trunk/test/CodeGen/AArch64/GlobalISel/arm64-callingconv.ll

Modified: llvm/trunk/lib/Target/AArch64/AArch64CallLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AArch64/AArch64CallLowering.cpp?rev=296754&r1=296753&r2=296754&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AArch64/AArch64CallLowering.cpp (original)
+++ llvm/trunk/lib/Target/AArch64/AArch64CallLowering.cpp Thu Mar  2 09:34:18 2017
@@ -136,7 +136,6 @@ struct OutgoingArgHandler : public CallL
     MIRBuilder.buildGEP(AddrReg, SPReg, OffsetReg);
 
     MPO = MachinePointerInfo::getStack(MIRBuilder.getMF(), Offset);
-    StackSize = std::max(StackSize, Size + Offset);
     return AddrReg;
   }
 
@@ -158,9 +157,14 @@ struct OutgoingArgHandler : public CallL
                  CCValAssign::LocInfo LocInfo,
                  const CallLowering::ArgInfo &Info,
                  CCState &State) override {
+    bool Res;
     if (Info.IsFixed)
-      return AssignFn(ValNo, ValVT, LocVT, LocInfo, Info.Flags, State);
-    return  AssignFnVarArg(ValNo, ValVT, LocVT, LocInfo, Info.Flags, State);
+      Res = AssignFn(ValNo, ValVT, LocVT, LocInfo, Info.Flags, State);
+    else
+      Res = AssignFnVarArg(ValNo, ValVT, LocVT, LocInfo, Info.Flags, State);
+
+    StackSize = State.getNextStackOffset();
+    return Res;
   }
 
   MachineInstrBuilder MIB;

Modified: llvm/trunk/test/CodeGen/AArch64/GlobalISel/arm64-callingconv.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/AArch64/GlobalISel/arm64-callingconv.ll?rev=296754&r1=296753&r2=296754&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/AArch64/GlobalISel/arm64-callingconv.ll (original)
+++ llvm/trunk/test/CodeGen/AArch64/GlobalISel/arm64-callingconv.ll Thu Mar  2 09:34:18 2017
@@ -80,3 +80,17 @@ define void @test_varargs() {
   call void(i32, double, i64, ...) @varargs(i32 42, double 1.0, i64 12, i8 3, i16 1, i32 4, float 1.0, double 2.0)
   ret void
 }
+
+; signext/zeroext parameters on the stack: not part of any real ABI as far as I
+; know, but ELF currently allocates 8 bytes for a signext parameter on the
+; stack. The ADJCALLSTACK ops should reflect this, even if the difference is
+; theoretical.
+declare void @stack_ext_needed([8 x i64], i8 signext %in)
+; CHECK-LABEL: name: test_stack_ext_needed
+; CHECK: ADJCALLSTACKDOWN 8
+; CHECK: BL @stack_ext_needed
+; CHECK: ADJCALLSTACKUP 8
+define void @test_stack_ext_needed() {
+  call void @stack_ext_needed([8 x i64] undef, i8 signext 42)
+  ret void
+}