[RISCV] Decode vtype with reserved fields to raw immediate

This patch fixes a crash when doing "llvm-objdump -D --mattr=+experimental-v" against an object file which happens to keep a word that can be decoded to VSETVLI & VSETIVLI with reserved vlmul[2:0]=4. All vtype values with reserved fields (vlmul[2:0]=4, vsew[2:0]=0b1xx, non-zero bits 8/9/10) are printed to raw immediate. Reviewed By: jhenderson, jrtc27, craig.topper Differential Revision: https://reviews.llvm.org/D114581
llvm · Nov 30, 2021 · 29d4230 · 29d4230
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commit 29d4230
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diff --git a/llvm/lib/Target/RISCV/MCTargetDesc/RISCVInstPrinter.cpp b/llvm/lib/Target/RISCV/MCTargetDesc/RISCVInstPrinter.cpp
@@ -170,6 +170,14 @@ void RISCVInstPrinter::printAtomicMemOp(const MCInst *MI, unsigned OpNo,
 void RISCVInstPrinter::printVTypeI(const MCInst *MI, unsigned OpNo,
                                    const MCSubtargetInfo &STI, raw_ostream &O) {
   unsigned Imm = MI->getOperand(OpNo).getImm();
+  // Print the raw immediate for reserved values: vlmul[2:0]=4, vsew[2:0]=0b1xx,
+  // or non-zero bits 8/9/10.
+  if (RISCVVType::getVLMUL(Imm) == RISCVII::VLMUL::LMUL_RESERVED ||
+      RISCVVType::getSEW(Imm) > 64 || (Imm & 0x700) != 0) {
+    O << Imm;
+    return;
+  }
+  // Print the text form.
   RISCVVType::printVType(Imm, O);
 }
 

diff --git a/llvm/test/MC/RISCV/rvv/vsetvl-invalid.s b/llvm/test/MC/RISCV/rvv/vsetvl-invalid.s
@@ -0,0 +1,40 @@
+# RUN: llvm-mc -filetype=obj -triple=riscv32 %s \
+# RUN:     | llvm-objdump -d --mattr=+experimental-v - | FileCheck %s
+# RUN: llvm-mc -filetype=obj -triple=riscv64 %s \
+# RUN:     | llvm-objdump -d --mattr=+experimental-v - | FileCheck %s
+
+# CHECK: vsetvli a1, a0, e64, m1, tu, mu
+.word 0x018575d7
+
+# CHECK: vsetvli a1, a0, 28
+.word 0x01c575d7
+
+# CHECK: vsetvli a1, a0, 36
+.word 0x024575d7
+
+# CHECK: vsetvli a1, a0, 41
+.word 0x029575d7
+
+# CHECK: vsetvli a1, a0, 272
+.word 0x110575d7
+
+# CHECK: vsetvli a1, a0, e64, mf8, tu, mu
+.word 0x01d575d7
+
+# CHECK: vsetivli a1, 16, e8, m4, tu, mu
+.word 0xc02875d7
+
+# CHECK: vsetivli a1, 16, 12
+.word 0xc0c875d7
+
+# CHECK: vsetivli a1, 16, 20
+.word 0xc14875d7
+
+# CHECK: vsetivli a1, 16, 56
+.word 0xc38875d7
+
+# CHECK: vsetivli a1, 16, 259
+.word 0xd03875d7
+
+# CHECK: vsetivli a1, 16, e8, mf4, tu, mu
+.word 0xc06875d7