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).

llvm-svn: 296754

2 files changed, 21 insertions, 3 deletions

diff --git a/llvm/lib/Target/AArch64/AArch64CallLowering.cpp b/llvm/lib/Target/AArch64/AArch64CallLowering.cpp
index 6148359da81..b1b98708753 100644
--- a/llvm/lib/Target/AArch64/AArch64CallLowering.cpp
+++ b/llvm/lib/Target/AArch64/AArch64CallLowering.cpp
@@ -136,7 +136,6 @@ struct OutgoingArgHandler : public CallLowering::ValueHandler {
     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 CallLowering::ValueHandler {
                  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;
diff --git a/llvm/test/CodeGen/AArch64/GlobalISel/arm64-callingconv.ll b/llvm/test/CodeGen/AArch64/GlobalISel/arm64-callingconv.ll
index 350ae0e4c08..59b9bb49f0e 100644
--- a/llvm/test/CodeGen/AArch64/GlobalISel/arm64-callingconv.ll
+++ b/llvm/test/CodeGen/AArch64/GlobalISel/arm64-callingconv.ll
@@ -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
+}