[clang] [clang-tools-extra] [llvm] [libc] [compiler-rt] [libcxx] [flang] [LoongArch] Fixing the incorrect return value of LoongArchTTIImpl::getRegisterBitWidth (PR #79441)

[via cfe-commits]

https://github.com/wangleiat updated https://github.com/llvm/llvm-project/pull/79441

>From 6231f5435a9735e6c9333c177f2e802a7ad1f901 Mon Sep 17 00:00:00 2001
From: wanglei <wanglei at loongson.cn>
Date: Thu, 25 Jan 2024 19:25:37 +0800
Subject: [PATCH] [LoongArch] Fixing the incorrect return value of
 LoongArchTTIImpl::getRegisterBitWidth

When we do not enable vector features, we should return the default
value (TargetTransformInfoImplBase::getRegisterBitWidth) instead of
zero.

This should fix the LoongArch buildbot breakage from #78943.
https://lab.llvm.org/staging/#/builders/5
---
 .../Target/LoongArch/LoongArchTargetTransformInfo.cpp | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/llvm/lib/Target/LoongArch/LoongArchTargetTransformInfo.cpp b/llvm/lib/Target/LoongArch/LoongArchTargetTransformInfo.cpp
index 04349aa52b5408..d47dded9ea6ecf 100644
--- a/llvm/lib/Target/LoongArch/LoongArchTargetTransformInfo.cpp
+++ b/llvm/lib/Target/LoongArch/LoongArchTargetTransformInfo.cpp
@@ -21,17 +21,20 @@ using namespace llvm;
 
 TypeSize LoongArchTTIImpl::getRegisterBitWidth(
     TargetTransformInfo::RegisterKind K) const {
+  TypeSize DefSize = TargetTransformInfoImplBase::getRegisterBitWidth(K);
   switch (K) {
   case TargetTransformInfo::RGK_Scalar:
     return TypeSize::getFixed(ST->is64Bit() ? 64 : 32);
   case TargetTransformInfo::RGK_FixedWidthVector:
-    if (ST->hasExtLASX() && ST->hasExpAutoVec())
+    if (!ST->hasExpAutoVec())
+      return DefSize;
+    if (ST->hasExtLASX())
       return TypeSize::getFixed(256);
-    if (ST->hasExtLSX() && ST->hasExpAutoVec())
+    if (ST->hasExtLSX())
       return TypeSize::getFixed(128);
-    return TypeSize::getFixed(0);
+    [[fallthrough]];
   case TargetTransformInfo::RGK_ScalableVector:
-    return TypeSize::getScalable(0);
+    return DefSize;
   }
 
   llvm_unreachable("Unsupported register kind");