[PATCH] D136106: [clang][RISCV] Set vscale_range attribute based on VLEN

[Philip Reames via Phabricator via llvm-commits]

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Follow up on D135894 <https://reviews.llvm.org/D135894>, restructure code to work in terms of minimum and maximum VLEN coming from RISCVISAInfo.cpp.

In the original review, I'd mentioned that MinVLEN was sometimes zero.  That's still true, but apparently only happens if you specify multiple extensions in the -target_feature string.  So, we can at least test "v" and "zve64x" on their own before I go figure out exactly what's going wrong regarding e.g. parsing "+v,+zvl512b".


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D136106

Files:
  clang/lib/Basic/Targets/RISCV.cpp
  clang/test/CodeGen/riscv-vector-bits-vscale-range.c
  llvm/include/llvm/Support/RISCVISAInfo.h


Index: llvm/include/llvm/Support/RISCVISAInfo.h
===================================================================
--- llvm/include/llvm/Support/RISCVISAInfo.h
+++ llvm/include/llvm/Support/RISCVISAInfo.h
@@ -60,6 +60,7 @@
   unsigned getXLen() const { return XLen; };
   unsigned getFLen() const { return FLen; };
   unsigned getMinVLen() const { return MinVLen; }
+  unsigned getMaxVLen() const { return 65536; }
   unsigned getMaxELen() const { return MaxELen; }
   unsigned getMaxELenFp() const { return MaxELenFp; }
 
Index: clang/test/CodeGen/riscv-vector-bits-vscale-range.c
===================================================================
--- clang/test/CodeGen/riscv-vector-bits-vscale-range.c
+++ clang/test/CodeGen/riscv-vector-bits-vscale-range.c
@@ -9,11 +9,13 @@
 // RUN: %clang_cc1 -triple riscv64-none-linux-gnu -target-feature +v -mvscale-min=8 -S -emit-llvm -o - %s | FileCheck %s -D#VBITS=8 --check-prefix=CHECK-NOMAX
 // RUN: %clang_cc1 -triple riscv64-none-linux-gnu -target-feature +v -mvscale-min=16 -S -emit-llvm -o - %s | FileCheck %s -D#VBITS=16 --check-prefix=CHECK-NOMAX
 // RUN: %clang_cc1 -triple riscv64-none-linux-gnu -target-feature +v -mvscale-min=1 -mvscale-max=0 -S -emit-llvm -o - %s | FileCheck %s --check-prefix=CHECK-UNBOUNDED
-// RUN: %clang_cc1 -triple riscv64-none-linux-gnu -target-feature +v -S -emit-llvm -o - %s | FileCheck %s --check-prefix=CHECK-NONE
+// RUN: %clang_cc1 -triple riscv64-none-linux-gnu -target-feature +v -S -emit-llvm -o - %s | FileCheck %s --check-prefix=CHECK-V
+// RUN: %clang_cc1 -triple riscv64-none-linux-gnu -target-feature +zve64x -S -emit-llvm -o - %s | FileCheck %s --check-prefix=CHECK-ZVE64
 
 // 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: attributes #0 = { {{.*}} vscale_range(2,1024) {{.*}} }
+// CHECK-V: attributes #0 = { {{.*}} vscale_range(2,1024) {{.*}} }
+// CHECK-ZVE64: attributes #0 = { {{.*}} vscale_range(1,1024) {{.*}} }
 void func(void) {}
Index: clang/lib/Basic/Targets/RISCV.cpp
===================================================================
--- clang/lib/Basic/Targets/RISCV.cpp
+++ clang/lib/Basic/Targets/RISCV.cpp
@@ -252,9 +252,11 @@
     return std::pair<unsigned, unsigned>(
         LangOpts.VScaleMin ? LangOpts.VScaleMin : 1, LangOpts.VScaleMax);
 
-  if (hasFeature("v"))
-    // Minimum VLEN=128, Maximum VLEN=64k, and RISCV::RVVBitsPerBlock is 64.
-    return std::pair<unsigned, unsigned>(2, 1024);
+  if (unsigned MinVLen = ISAInfo->getMinVLen()) {
+    unsigned MaxVLen = ISAInfo->getMaxVLen();
+    // RISCV::RVVBitsPerBlock is 64.
+    return std::pair<unsigned, unsigned>(MinVLen/64, MaxVLen/64);
+  }
 
   return None;
 }


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