[clang] [llvm] [clang][RISCV] Change default abi when only have f extension but no d extension (PR #73489)

[Jianjian Guan via cfe-commits]

https://github.com/jacquesguan created https://github.com/llvm/llvm-project/pull/73489

Now we have default abi lp64 for rv64if and ilp32 for rv32if, which is different with riscv-gnu-toolchain. In https://github.com/riscv-collab/riscv-gnu-toolchain/blob/8e9fb09a0c4b1e566492ee6f42e8c1fa5ef7e0c2/configure#L3385 when have f and not d, it prefers lp64f/ilp32f but no soft float. This patch tries to make their behaviors consistent.

>From b41c0a913a4ef81e650762a5ede5ae702860f001 Mon Sep 17 00:00:00 2001
From: Jianjian GUAN <jacquesguan at me.com>
Date: Mon, 27 Nov 2023 16:14:04 +0800
Subject: [PATCH] [clang][RISCV] Change default abi when only have f extension
 but no d extension

Now we have default abi lp64 for rv64if and ilp32 for rv32if, which is different with riscv-gnu-toolchain.
In https://github.com/riscv-collab/riscv-gnu-toolchain/blob/8e9fb09a0c4b1e566492ee6f42e8c1fa5ef7e0c2/configure#L3385 when have f but not, it prefers lp64f/ilp32f but no soft float. This patch tries to make their behaviors consistent.
---
 clang/test/Driver/riscv-abi.c     | 14 +++++++++-----
 llvm/lib/Support/RISCVISAInfo.cpp |  4 ++++
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/clang/test/Driver/riscv-abi.c b/clang/test/Driver/riscv-abi.c
index e67f790e0de0e59..16568271564c797 100644
--- a/clang/test/Driver/riscv-abi.c
+++ b/clang/test/Driver/riscv-abi.c
@@ -4,8 +4,6 @@
 // RUN:   | FileCheck -check-prefix=CHECK-ILP32 %s
 // RUN: %clang --target=riscv32-unknown-elf %s -### -march=rv32imc 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK-ILP32 %s
-// RUN: %clang --target=riscv32-unknown-elf %s -### -march=rv32imf 2>&1 \
-// RUN:   | FileCheck -check-prefix=CHECK-ILP32 %s
 // RUN: %clang --target=riscv32-unknown-elf -x assembler %s -### 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK-ILP32 %s
 // RUN: %clang --target=riscv32-unknown-elf -x assembler %s -### \
@@ -24,6 +22,10 @@
 
 // RUN: %clang --target=riscv32-unknown-elf %s -### -march=rv32if -mabi=ilp32f 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK-ILP32F %s
+// RUN: %clang --target=riscv32-unknown-elf %s -### -mabi=ilp32f 2>&1 \
+// RUN:   | FileCheck -check-prefix=CHECK-ILP32F %s
+// RUN: %clang --target=riscv32-unknown-elf %s -### -march=rv32if 2>&1 \
+// RUN:   | FileCheck -check-prefix=CHECK-ILP32F %s
 
 // CHECK-ILP32F: "-target-abi" "ilp32f"
 
@@ -51,8 +53,6 @@
 // RUN:   | FileCheck -check-prefix=CHECK-LP64 %s
 // RUN: %clang --target=riscv64-unknown-elf %s -### -march=rv64imc 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK-LP64 %s
-// RUN: %clang --target=riscv64-unknown-elf %s -### -march=rv64imf 2>&1 \
-// RUN:   | FileCheck -check-prefix=CHECK-LP64 %s
 // RUN: %clang --target=riscv64-unknown-elf -x assembler %s -### 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK-LP64  %s
 // RUN: %clang --target=riscv64-unknown-elf -x assembler %s -### \
@@ -60,7 +60,11 @@
 
 // CHECK-LP64: "-target-abi" "lp64"
 
-// RUN:  not %clang --target=riscv64-unknown-elf %s -### -march=rv64f -mabi=lp64f 2>&1 \
+// RUN:  %clang --target=riscv64-unknown-elf %s -### -march=rv64if -mabi=lp64f 2>&1 \
+// RUN:   | FileCheck -check-prefix=CHECK-LP64F %s
+// RUN:  %clang --target=riscv64-unknown-elf %s -### -mabi=lp64f 2>&1 \
+// RUN:   | FileCheck -check-prefix=CHECK-LP64F %s
+// RUN:  %clang --target=riscv64-unknown-elf %s -### -march=rv64if 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK-LP64F %s
 
 // CHECK-LP64F: "-target-abi" "lp64f"
diff --git a/llvm/lib/Support/RISCVISAInfo.cpp b/llvm/lib/Support/RISCVISAInfo.cpp
index 6322748430063ce..24d0d40cbc74ebc 100644
--- a/llvm/lib/Support/RISCVISAInfo.cpp
+++ b/llvm/lib/Support/RISCVISAInfo.cpp
@@ -1292,12 +1292,16 @@ StringRef RISCVISAInfo::computeDefaultABI() const {
   if (XLen == 32) {
     if (hasExtension("d"))
       return "ilp32d";
+    if (hasExtension("f"))
+      return "ilp32f";
     if (hasExtension("e"))
       return "ilp32e";
     return "ilp32";
   } else if (XLen == 64) {
     if (hasExtension("d"))
       return "lp64d";
+    if (hasExtension("f"))
+      return "lp64f";
     if (hasExtension("e"))
       return "lp64e";
     return "lp64";