[llvm] 9a8f3b1 - [clang][RISCV] Set vscale_range attribute based on VLEN

[Philip Reames via llvm-commits]

Author: Philip Reames
Date: 2022-10-19T16:14:33-07:00
New Revision: 9a8f3b113d05d94d9aaacdf511365dde4e35ce4f

URL: https://github.com/llvm/llvm-project/commit/9a8f3b113d05d94d9aaacdf511365dde4e35ce4f
DIFF: https://github.com/llvm/llvm-project/commit/9a8f3b113d05d94d9aaacdf511365dde4e35ce4f.diff

LOG: [clang][RISCV] Set vscale_range attribute based on VLEN

Follow up on 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. This turns out to be a case of human error, combined with really bad (lack of) error reporting.

This patch adds appropriate tests for various vector extension combinations to show the mechanism works, but doesn't try to provide exhaustive coverage of the extension interactions. Presumably, that is already covered in existing tests elsewhere.

Differential Revision: https://reviews.llvm.org/D136106

Added: 
    

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

Removed: 
    


################################################################################
diff  --git a/clang/lib/Basic/Targets/RISCV.cpp b/clang/lib/Basic/Targets/RISCV.cpp
index b94187f939f27..08da01602599f 100644
--- a/clang/lib/Basic/Targets/RISCV.cpp
+++ b/clang/lib/Basic/Targets/RISCV.cpp
@@ -252,9 +252,11 @@ RISCVTargetInfo::getVScaleRange(const LangOptions &LangOpts) const {
     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;
 }

diff  --git a/clang/test/CodeGen/riscv-vector-bits-vscale-range.c b/clang/test/CodeGen/riscv-vector-bits-vscale-range.c
index 067669fa289d2..9fbb9795657b3 100644
--- a/clang/test/CodeGen/riscv-vector-bits-vscale-range.c
+++ b/clang/test/CodeGen/riscv-vector-bits-vscale-range.c
@@ -9,11 +9,17 @@
 // 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 +v -target-feature +zvl512b -S -emit-llvm -o - %s | FileCheck %s --check-prefix=CHECK-ZVL
+// RUN: %clang_cc1 -triple riscv64-none-linux-gnu -target-feature +zve64x -S -emit-llvm -o - %s | FileCheck %s --check-prefix=CHECK-ZVE64
+// RUN: %clang_cc1 -triple riscv64-none-linux-gnu -target-feature +zve64f -target-feature +f -S -emit-llvm -o - %s | FileCheck %s --check-prefix=CHECK-ZVE64
+// RUN: %clang_cc1 -triple riscv64-none-linux-gnu -target-feature +zve64d -target-feature +f -target-feature +d -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-ZVL: attributes #0 = { {{.*}} vscale_range(8,1024) {{.*}} }
+// CHECK-ZVE64: attributes #0 = { {{.*}} vscale_range(1,1024) {{.*}} }
 void func(void) {}

diff  --git a/llvm/include/llvm/Support/RISCVISAInfo.h b/llvm/include/llvm/Support/RISCVISAInfo.h
index eac6cc0925fb3..ced3baf416fcb 100644
--- a/llvm/include/llvm/Support/RISCVISAInfo.h
+++ b/llvm/include/llvm/Support/RISCVISAInfo.h
@@ -60,6 +60,7 @@ class RISCVISAInfo {
   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; }