[llvm] [RISCV] Fix Branch/Jump Immediates (PR #120658)
Sam Elliott via llvm-commits
llvm-commits at lists.llvm.org
Thu Dec 19 16:21:59 PST 2024
https://github.com/lenary created https://github.com/llvm/llvm-project/pull/120658
This extends the work done in 2b2b8409e6848361577be404bd0ae47a097f0e0c to cover all rv32 signed immediates.
Binutils seems to accept these for branches and jumps, but doesn't for `c.addi16sp` - which I think is a bug on their side. How they are assembled by binutils looks a bit strange (with `32-bit branch; jump` pseudos and a relocation to an absolute symbol on the jump, even for the Zca instructions), but seems to do the equivalent thing.
>From a96e17186f5be8329ec91f715b555c4d54b03abe Mon Sep 17 00:00:00 2001
From: Sam Elliott <quic_aelliott at quicinc.com>
Date: Thu, 19 Dec 2024 15:57:08 -0800
Subject: [PATCH] [RISCV] Fix Branch/Jump Immediates
This extends the work done in 2b2b8409e6848361577be404bd0ae47a097f0e0c
to cover all rv32 signed immediates.
Binutils seems to accept these for branches and jumps, but doesn't for
`c.addi16sp` - which I think is a bug on their side. How they are
assembled by binutils looks a bit strange (with `32-bit branch; jump`
pseudos and a relocation to an absolute symbol on the jump, even for the
Zca instructions), but seems to do the equivalent thing.
---
.../Target/RISCV/AsmParser/RISCVAsmParser.cpp | 8 ++--
llvm/test/MC/RISCV/rv32c-only-valid.s | 28 ++++++++++++
llvm/test/MC/RISCV/rv32i-only-valid.s | 45 ++++++++++++++++++-
3 files changed, 77 insertions(+), 4 deletions(-)
diff --git a/llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp b/llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp
index 5b9946e5132e40..9dcf2e973e6c58 100644
--- a/llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp
+++ b/llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp
@@ -530,7 +530,7 @@ struct RISCVOperand final : public MCParsedAsmOperand {
if (!IsConstantImm)
IsValid = RISCVAsmParser::classifySymbolRef(getImm(), VK);
else
- IsValid = isShiftedInt<N - 1, 1>(Imm);
+ IsValid = isShiftedInt<N - 1, 1>(fixImmediateForRV32(Imm, isRV64Imm()));
return IsValid && VK == RISCVMCExpr::VK_RISCV_None;
}
@@ -943,7 +943,8 @@ struct RISCVOperand final : public MCParsedAsmOperand {
RISCVMCExpr::VariantKind VK = RISCVMCExpr::VK_RISCV_None;
int64_t Imm;
bool IsConstantImm = evaluateConstantImm(getImm(), Imm, VK);
- return IsConstantImm && isShiftedInt<7, 5>(Imm) &&
+ return IsConstantImm &&
+ isShiftedInt<7, 5>(fixImmediateForRV32(Imm, isRV64Imm())) &&
VK == RISCVMCExpr::VK_RISCV_None;
}
@@ -955,7 +956,8 @@ struct RISCVOperand final : public MCParsedAsmOperand {
int64_t Imm;
RISCVMCExpr::VariantKind VK = RISCVMCExpr::VK_RISCV_None;
bool IsConstantImm = evaluateConstantImm(getImm(), Imm, VK);
- return IsConstantImm && (Imm != 0) && isShiftedInt<6, 4>(Imm) &&
+ return IsConstantImm && (Imm != 0) &&
+ isShiftedInt<6, 4>(fixImmediateForRV32(Imm, isRV64Imm())) &&
VK == RISCVMCExpr::VK_RISCV_None;
}
diff --git a/llvm/test/MC/RISCV/rv32c-only-valid.s b/llvm/test/MC/RISCV/rv32c-only-valid.s
index 70f358ef24fce1..3321aff115c4d0 100644
--- a/llvm/test/MC/RISCV/rv32c-only-valid.s
+++ b/llvm/test/MC/RISCV/rv32c-only-valid.s
@@ -26,3 +26,31 @@ c.jal 2046
# CHECK-ASM: c.addi a1, -1
# CHECK-ASM: encoding: [0xfd,0x15]
c.addi a1, 0xffffffff
+
+# CHECK-OBJ: c.addi16sp sp, -352
+# CHECK-ASM: c.addi16sp sp, -352
+# CHECK-ASM: encoding: [0x0d,0x71]
+c.addi16sp sp, 0xfffffea0
+
+## Branch and Jump immediates are relative but printed as their absolute address
+## when disassembling.
+
+# CHECK-OBJ: c.beqz a2, 0xffffff06
+# CHECK-ASM: c.beqz a2, -256
+# CHECK-ASM: encoding: [0x01,0xd2]
+c.beqz a2, 0xffffff00
+
+# CHECK-OBJ: c.beqz a0, 0xffffff16
+# CHECK-ASM: .insn cb 1, 6, a0, -242
+# CHECK-ASM: encoding: [0x19,0xd5]
+.insn cb 1, 6, a0, 0xffffff0e
+
+# CHECK-OBJ: c.jal 0xfffffab4
+# CHECK-ASM: c.jal -1366
+# CHECK-ASM: encoding: [0x6d,0x34]
+c.jal 0xfffffaaa
+
+# CHECK-OBJ: c.j 0xfffffcd8
+# CHECK-ASM: .insn cj 1, 5, -820
+# CHECK-ASM: encoding: [0xf1,0xb1]
+.insn cj 1, 5, 0xfffffccc
diff --git a/llvm/test/MC/RISCV/rv32i-only-valid.s b/llvm/test/MC/RISCV/rv32i-only-valid.s
index 806219fd4b37d8..74232e3c419f14 100644
--- a/llvm/test/MC/RISCV/rv32i-only-valid.s
+++ b/llvm/test/MC/RISCV/rv32i-only-valid.s
@@ -2,7 +2,7 @@
# RUN: | FileCheck -check-prefixes=CHECK-ASM,CHECK-ASM-AND-OBJ %s
# RUN: llvm-mc -filetype=obj -triple=riscv32 < %s \
# RUN: | llvm-objdump -M no-aliases --no-print-imm-hex -d -r - \
-# RUN: | FileCheck -check-prefixes=CHECK-ASM-AND-OBJ %s
+# RUN: | FileCheck -check-prefixes=CHECK-OBJ,CHECK-ASM-AND-OBJ %s
# CHECK-ASM-AND-OBJ: addi a0, a1, -1
# CHECK-ASM: encoding: [0x13,0x85,0xf5,0xff]
@@ -16,3 +16,46 @@ lw a1, 0xfffff9ab(a2)
# CHECK-ASM-AND-OBJ: sw a1, -8(a2)
# CHECK-ASM: encoding: [0x23,0x2c,0xb6,0xfe]
sw a1, 0xfffffff8(a2)
+
+## Branch and Jump immediates are relative but printed as their absolute address
+## when disassembling.
+
+# CHECK-ASM: beq t0, t1, -4096
+# CHECK-ASM: encoding: [0x63,0x80,0x62,0x80]
+# CHECK-OBJ: beq t0, t1, 0xfffff010
+beq t0, t1, 0xfffff000
+
+# CHECK-ASM: bne t1, t2, -4082
+# CHECK-ASM: encoding: [0x63,0x17,0x73,0x80]
+# CHECK-OBJ: bne t1, t2, 0xfffff022
+bne t1, t2, 0xfffff00e
+
+# CHECK-ASM: beq t2, zero, -3550
+# CHECK-ASM: encoding: [0x63,0x81,0x03,0xa2]
+# CHECK-OBJ: beq t2, zero, 0xfffff23a
+beqz t2, 0xfffff222
+
+# CHECK-ASM: .insn b 99, 0, a0, a1, -3004
+# CHECK-ASM: encoding: [0x63,0x02,0xb5,0xc4]
+# CHECK-OBJ: beq a0, a1, 0xfffff460
+.insn b BRANCH, 0, a0, a1, 0xfffff444
+
+# CHECK-ASM: jal ra, -2458
+# CHECK-ASM: encoding: [0xef,0xf0,0x6f,0xe6]
+# CHECK-OBJ: jal ra, 0xfffff686
+jal ra, 0xfffff666
+
+# CHECK-ASM: jal ra, -1912
+# CHECK-ASM: encoding: [0xef,0xf0,0x9f,0x88]
+# CHECK-OBJ: jal ra, 0xfffff8ac
+jal 0xfffff888
+
+# CHECK-ASM: jal zero, -1366
+# CHECK-ASM: encoding: [0x6f,0xf0,0xbf,0xaa]
+# CHECK-OBJ: jal zero, 0xfffffad2
+j 0xfffffaaa
+
+# CHECK-ASM: .insn j 111, a0, -820
+# CHECK-ASM: encoding: [0x6f,0x65,0xe6,0xff]
+# CHECK-OBJ: jal a0, 0xfff6682a
+.insn j JAL, a0, 0xfffffccc
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