[PATCH] D130311: [RISCV] Enable strict FP in clang as long as Zve* or V are not enabled.

[Craig Topper via Phabricator via cfe-commits]

craig.topper created this revision.
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As far as I know, scalar support for strict FP in the backend is
complete. Unfortunately, vector is missing.

This patch enables strict FP support as long as there's no chance
of any vector code. This isn't ideal, but it's a start.

Given the proximity to the LLVM 15 branch, I don't intend to commit this
until after that if this is approved.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D130311

Files:
  clang/lib/Basic/Targets/RISCV.cpp
  clang/lib/Basic/Targets/RISCV.h
  clang/test/CodeGen/builtin_float_strictfp.c
  llvm/lib/Target/RISCV/RISCVISelLowering.cpp


Index: llvm/lib/Target/RISCV/RISCVISelLowering.cpp
===================================================================
--- llvm/lib/Target/RISCV/RISCVISelLowering.cpp
+++ llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -928,6 +928,10 @@
     }
   }
 
+  // FIXME: Strict FP support is incomplete for vectors.
+  if (!Subtarget.hasVInstructions())
+    IsStrictFPEnabled = true;
+
   // Function alignments.
   const Align FunctionAlignment(Subtarget.hasStdExtC() ? 2 : 4);
   setMinFunctionAlignment(FunctionAlignment);
Index: clang/test/CodeGen/builtin_float_strictfp.c
===================================================================
--- clang/test/CodeGen/builtin_float_strictfp.c
+++ clang/test/CodeGen/builtin_float_strictfp.c
@@ -1,5 +1,6 @@
 // RUN: %clang_cc1 -no-opaque-pointers -emit-llvm -triple x86_64-windows-pc -ffp-exception-behavior=maytrap -o - %s | FileCheck %s --check-prefixes=CHECK,FP16
 // RUN: %clang_cc1 -no-opaque-pointers -emit-llvm -triple ppc64-be -ffp-exception-behavior=maytrap -o - %s | FileCheck %s --check-prefixes=CHECK,NOFP16
+// RUN: %clang_cc1 -no-opaque-pointers -emit-llvm -triple riscv64 -ffp-exception-behavior=maytrap -o - %s | FileCheck %s --check-prefixes=CHECK,FP16
 
 // test to ensure that these builtins don't do the variadic promotion of float->double.
 
Index: clang/lib/Basic/Targets/RISCV.h
===================================================================
--- clang/lib/Basic/Targets/RISCV.h
+++ clang/lib/Basic/Targets/RISCV.h
@@ -41,6 +41,7 @@
     HasRISCVVTypes = true;
     MCountName = "_mcount";
     HasFloat16 = true;
+    HasStrictFP = true;
   }
 
   bool setCPU(const std::string &Name) override {
Index: clang/lib/Basic/Targets/RISCV.cpp
===================================================================
--- clang/lib/Basic/Targets/RISCV.cpp
+++ clang/lib/Basic/Targets/RISCV.cpp
@@ -282,6 +282,10 @@
   if (ABI.empty())
     ABI = ISAInfo->computeDefaultABI().str();
 
+  // StrictFP support for vectors is incomplete.
+  if (ISAInfo->hasExtension("zve32x"))
+    HasStrictFP = false;
+
   return true;
 }
 


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