[IR] Remove options to make scalable TypeSize access a warning (llvm#156336)

This removes the `LLVM_ENABLE_STRICT_FIXED_SIZE_VECTORS` cmake option
and the `-treat-scalable-fixed-error-as-warning` opt flag.

We stopped treating these as warnings by default a long time ago
(62f09d7), so I don't think it makes
sense to retain these options at this point. Accessing a scalable
TypeSize as fixed should always result in an error.

Author: nikic

llvm/CMakeLists.txt

@@ -706,18 +706,6 @@ endif()
 
 option(LLVM_ENABLE_EXPENSIVE_CHECKS "Enable expensive checks" OFF)
 
-# While adding scalable vector support to LLVM, we temporarily want to
-# allow an implicit conversion of TypeSize to uint64_t, and to allow
-# code to get the fixed number of elements from a possibly scalable vector.
-# This CMake flag enables a more strict mode where it asserts that the type
-# is not a scalable vector type.
-#
-# Enabling this flag makes it easier to find cases where the compiler makes
-# assumptions on the size being 'fixed size', when building tests for
-# SVE/SVE2 or other scalable vector architectures.
-option(LLVM_ENABLE_STRICT_FIXED_SIZE_VECTORS
-       "Enable assertions that type is not scalable in implicit conversion from TypeSize to uint64_t and calls to getNumElements" OFF)
-
 set(LLVM_ABI_BREAKING_CHECKS "WITH_ASSERTS" CACHE STRING
   "Enable abi-breaking checks.  Can be WITH_ASSERTS, FORCE_ON or FORCE_OFF.")
 

llvm/cmake/modules/HandleLLVMOptions.cmake

@@ -201,10 +201,6 @@ if (LLVM_USES_LIBSTDCXX)
   endif()
 endif()
 
-if (LLVM_ENABLE_STRICT_FIXED_SIZE_VECTORS)
-  add_compile_definitions(STRICT_FIXED_SIZE_VECTORS)
-endif()
-
 string(TOUPPER "${LLVM_ABI_BREAKING_CHECKS}" uppercase_LLVM_ABI_BREAKING_CHECKS)
 
 if( uppercase_LLVM_ABI_BREAKING_CHECKS STREQUAL "WITH_ASSERTS" )

llvm/include/llvm/CodeGen/ValueTypes.h

@@ -332,7 +332,7 @@ namespace llvm {
       assert(isVector() && "Invalid vector type!");
 
       if (isScalableVector())
-        llvm::reportInvalidSizeRequest(
+        llvm::reportFatalInternalError(
             "Possible incorrect use of EVT::getVectorNumElements() for "
             "scalable vector. Scalable flag may be dropped, use "
             "EVT::getVectorElementCount() instead");

llvm/include/llvm/CodeGenTypes/LowLevelType.h

@@ -159,7 +159,7 @@ class LLT {
   /// vector types.
   constexpr uint16_t getNumElements() const {
     if (isScalable())
-      llvm::reportInvalidSizeRequest(
+      llvm::reportFatalInternalError(
           "Possible incorrect use of LLT::getNumElements() for "
           "scalable vector. Scalable flag may be dropped, use "
           "LLT::getElementCount() instead");

llvm/include/llvm/CodeGenTypes/MachineValueType.h

@@ -294,7 +294,7 @@ namespace llvm {
 
     unsigned getVectorNumElements() const {
       if (isScalableVector())
-        llvm::reportInvalidSizeRequest(
+        llvm::reportFatalInternalError(
             "Possible incorrect use of MVT::getVectorNumElements() for "
             "scalable vector. Scalable flag may be dropped, use "
             "MVT::getVectorElementCount() instead");

llvm/include/llvm/Support/TypeSize.h

@@ -26,10 +26,6 @@
 
 namespace llvm {
 
-/// Reports a diagnostic message to indicate an invalid size request has been
-/// done on a scalable vector. This function may not return.
-LLVM_ABI void reportInvalidSizeRequest(const char *Msg);
-
 /// StackOffset holds a fixed and a scalable offset in bytes.
 class StackOffset {
   int64_t Fixed = 0;

llvm/lib/Support/CommandLine.cpp

@@ -2671,7 +2671,6 @@ static void initCommonOptions() {
   initSignalsOptions();
   initStatisticOptions();
   initTimerOptions();
-  initTypeSizeOptions();
   initWithColorOptions();
   initDebugOptions();
   initRandomSeedOptions();

llvm/lib/Support/DebugOptions.h

@@ -24,7 +24,6 @@ void initGraphWriterOptions();
 void initSignalsOptions();
 void initStatisticOptions();
 void initTimerOptions();
-void initTypeSizeOptions();
 void initWithColorOptions();
 void initDebugOptions();
 void initRandomSeedOptions();

llvm/lib/Support/TypeSize.cpp

@@ -7,49 +7,13 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Support/TypeSize.h"
-#include "llvm/Support/CommandLine.h"
-#include "llvm/Support/ManagedStatic.h"
-#include "llvm/Support/WithColor.h"
-
-#include "DebugOptions.h"
+#include "llvm/Support/Error.h"
 
 using namespace llvm;
 
-#ifndef STRICT_FIXED_SIZE_VECTORS
-namespace {
-struct CreateScalableErrorAsWarning {
-  /// The ScalableErrorAsWarning is a temporary measure to suppress errors from
-  /// using the wrong interface on a scalable vector.
-  static void *call() {
-    return new cl::opt<bool>(
-        "treat-scalable-fixed-error-as-warning", cl::Hidden,
-        cl::desc(
-            "Treat issues where a fixed-width property is requested from a "
-            "scalable type as a warning, instead of an error"));
-  }
-};
-} // namespace
-static ManagedStatic<cl::opt<bool>, CreateScalableErrorAsWarning>
-    ScalableErrorAsWarning;
-void llvm::initTypeSizeOptions() { *ScalableErrorAsWarning; }
-#else
-void llvm::initTypeSizeOptions() {}
-#endif
-
-void llvm::reportInvalidSizeRequest(const char *Msg) {
-#ifndef STRICT_FIXED_SIZE_VECTORS
-  if (*ScalableErrorAsWarning) {
-    WithColor::warning() << "Invalid size request on a scalable vector; " << Msg
-                         << "\n";
-    return;
-  }
-#endif
-  report_fatal_error("Invalid size request on a scalable vector.");
-}
-
 TypeSize::operator TypeSize::ScalarTy() const {
   if (isScalable()) {
-    reportInvalidSizeRequest(
+    reportFatalInternalError(
         "Cannot implicitly convert a scalable size to a fixed-width size in "
         "`TypeSize::operator ScalarTy()`");
     return getKnownMinValue();

llvm/test/CodeGen/AArch64/sms-order-physreg-deps.mir

@@ -1,4 +1,4 @@
-# RUN: llc --verify-machineinstrs -mtriple=aarch64 -o - %s -mcpu=a64fx -aarch64-enable-pipeliner -pipeliner-max-mii=100 -pipeliner-enable-copytophi=0 -debug-only=pipeliner -run-pass=pipeliner -treat-scalable-fixed-error-as-warning 2>&1 | FileCheck %s
+# RUN: llc --verify-machineinstrs -mtriple=aarch64 -o - %s -mcpu=a64fx -aarch64-enable-pipeliner -pipeliner-max-mii=100 -pipeliner-enable-copytophi=0 -debug-only=pipeliner -run-pass=pipeliner 2>&1 | FileCheck %s
 
 # REQUIRES: asserts