[llvm] [SystemZ] Use VT (not ArgVT) for SlotVT in LowerCall(). (PR #82475)

[Jonas Paulsson via llvm-commits]

https://github.com/JonPsson1 created https://github.com/llvm/llvm-project/pull/82475

When an integer argument is promoted and not split (like i72 -> i128 on a new machine with vector support), the SlotVT should be i128, which is stored in VT - not ArgVT.

Fixes #81417

>From c16c1cf20cd8c3e1e2c77c4341cf54c9a50a65d3 Mon Sep 17 00:00:00 2001
From: Jonas Paulsson <paulson1 at linux.ibm.com>
Date: Wed, 21 Feb 2024 09:29:16 +0100
Subject: [PATCH] [SystemZ] Use VT (not ArgVT) for SlotVT in LowerCall().

---
 .../lib/Target/SystemZ/SystemZISelLowering.cpp |  2 +-
 llvm/test/CodeGen/SystemZ/frame-29.ll          | 18 ++++++++++++++++++
 2 files changed, 19 insertions(+), 1 deletion(-)
 create mode 100644 llvm/test/CodeGen/SystemZ/frame-29.ll

diff --git a/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp b/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
index d92586f7d05d0d..3b85a6ac0371ed 100644
--- a/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
+++ b/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
@@ -1923,7 +1923,7 @@ SystemZTargetLowering::LowerCall(CallLoweringInfo &CLI,
         unsigned N = getNumRegistersForCallingConv(Ctx, CLI.CallConv, OrigArgVT);
         SlotVT = EVT::getIntegerVT(Ctx, PartVT.getSizeInBits() * N);
       } else {
-        SlotVT = Outs[I].ArgVT;
+        SlotVT = Outs[I].VT;
       }
       SDValue SpillSlot = DAG.CreateStackTemporary(SlotVT);
       int FI = cast<FrameIndexSDNode>(SpillSlot)->getIndex();
diff --git a/llvm/test/CodeGen/SystemZ/frame-29.ll b/llvm/test/CodeGen/SystemZ/frame-29.ll
new file mode 100644
index 00000000000000..6cc0d9e985e160
--- /dev/null
+++ b/llvm/test/CodeGen/SystemZ/frame-29.ll
@@ -0,0 +1,18 @@
+; RUN: llc %s -o - -mtriple=s390x-linux-gnu -mcpu=z16 -print-after=finalize-isel 2>&1 | FileCheck %s
+;
+; Test that the correct space is allocated for the outgoing stack argument.
+
+declare void @bar(i72 %Arg);
+
+define void @foo() {
+; CHECK-LABEL: # Machine code for function foo: IsSSA, TracksLiveness
+; CHECK-NEXT: Frame Objects:
+; CHECK-NEXT:   fi#0: size=1, align=2, at location [SP]
+; CHECK-NEXT:   fi#1: size=16, align=8, at location [SP]
+
+; CHECK-LABEL: foo:
+; CHECK: aghi %r15, -184
+  %1 = alloca i8, align 2
+  tail call fastcc void @bar(i72 2097168)
+  ret void
+}