[flang] Support -mvscale-min and mvscale-max on all targets (#74633)

We have other targets with scalable vectors (e.g.RISC-V), and there
doesn't seem to be any particular reason these options can't be used on
those targets.

Author: preames

flang/lib/Frontend/FrontendActions.cpp

@@ -710,8 +710,8 @@ void CodeGenAction::lowerHLFIRToFIR() {
 // TODO: We should get this from TargetInfo. However, that depends on
 // too much of clang, so for now, replicate the functionality.
 static std::optional<std::pair<unsigned, unsigned>>
-getVScaleRange(CompilerInstance &ci,
-               const Fortran::frontend::LangOptions &langOpts) {
+getVScaleRange(CompilerInstance &ci) {
+  const auto &langOpts = ci.getInvocation().getLangOpts();
   if (langOpts.VScaleMin || langOpts.VScaleMax)
     return std::pair<unsigned, unsigned>(
         langOpts.VScaleMin ? langOpts.VScaleMin : 1, langOpts.VScaleMax);
@@ -746,13 +746,9 @@ void CodeGenAction::generateLLVMIR() {
   const auto targetOpts = ci.getInvocation().getTargetOpts();
   const llvm::Triple triple(targetOpts.triple);
 
-  // Only get the vscale range if AArch64.
-  if (triple.isAArch64()) {
-    auto langOpts = ci.getInvocation().getLangOpts();
-    if (auto vsr = getVScaleRange(ci, langOpts)) {
-      config.VScaleMin = vsr->first;
-      config.VScaleMax = vsr->second;
-    }
+  if (auto vsr = getVScaleRange(ci)) {
+    config.VScaleMin = vsr->first;
+    config.VScaleMax = vsr->second;
   }
 
   // Create the pass pipeline

flang/test/Lower/RISCV/riscv-vector-bits-vscale-range.f90

@@ -0,0 +1,21 @@
+! REQUIRES: riscv-registered-target
+! RUN: %flang_fc1 -triple riscv64-none-linux-gnu -target-feature +v -mvscale-min=1 -mvscale-max=1  -emit-llvm -o - %s | FileCheck %s -D#VBITS=1
+! RUN: %flang_fc1 -triple riscv64-none-linux-gnu -target-feature +v -mvscale-min=2 -mvscale-max=2  -emit-llvm -o - %s | FileCheck %s -D#VBITS=2
+! RUN: %flang_fc1 -triple riscv64-none-linux-gnu -target-feature +v -mvscale-min=4 -mvscale-max=4  -emit-llvm -o - %s | FileCheck %s -D#VBITS=4
+! RUN: %flang_fc1 -triple riscv64-none-linux-gnu -target-feature +v -mvscale-min=8 -mvscale-max=8  -emit-llvm -o - %s | FileCheck %s -D#VBITS=8
+! RUN: %flang_fc1 -triple riscv64-none-linux-gnu -target-feature +v -mvscale-min=16 -mvscale-max=16  -emit-llvm -o - %s | FileCheck %s -D#VBITS=16
+! RUN: %flang_fc1 -triple riscv64-none-linux-gnu -target-feature +v -mvscale-min=1  -emit-llvm -o - %s | FileCheck %s -D#VBITS=1 --check-prefix=CHECK-NOMAX
+! RUN: %flang_fc1 -triple riscv64-none-linux-gnu -target-feature +v -mvscale-min=2  -emit-llvm -o - %s | FileCheck %s -D#VBITS=2 --check-prefix=CHECK-NOMAX
+! RUN: %flang_fc1 -triple riscv64-none-linux-gnu -target-feature +v -mvscale-min=4  -emit-llvm -o - %s | FileCheck %s -D#VBITS=4 --check-prefix=CHECK-NOMAX
+! RUN: %flang_fc1 -triple riscv64-none-linux-gnu -target-feature +v -mvscale-min=8  -emit-llvm -o - %s | FileCheck %s -D#VBITS=8 --check-prefix=CHECK-NOMAX
+! RUN: %flang_fc1 -triple riscv64-none-linux-gnu -target-feature +v -mvscale-min=16  -emit-llvm -o - %s | FileCheck %s -D#VBITS=16 --check-prefix=CHECK-NOMAX
+! RUN: %flang_fc1 -triple riscv64-none-linux-gnu -target-feature +v -mvscale-min=1 -mvscale-max=0  -emit-llvm -o - %s | FileCheck %s --check-prefix=CHECK-UNBOUNDED
+! RUN: %flang_fc1 -triple riscv64-none-linux-gnu -target-feature +v -emit-llvm -o - %s | FileCheck %s --check-prefix=CHECK-NONE
+
+! CHECK-LABEL: @func_() #0
+! CHECK: attributes #0 = {{{.*}} vscale_range([[#VBITS]],[[#VBITS]]) {{.*}}}
+! CHECK-NOMAX: attributes #0 = {{{.*}} vscale_range([[#VBITS]],0) {{.*}}}
+! CHECK-UNBOUNDED: attributes #0 = {{{.*}} vscale_range(1,0) {{.*}}}
+! CHECK-NONE-NOT: vscale_range
+subroutine func
+end subroutine func