[PATCH] D97970: [RISCV] Make the hasStdExtM() check in RISCVInstrInfo::getVLENFactoredAmount a fatal error rather than an assert.

[Craig Topper via Phabricator via llvm-commits]

craig.topper created this revision.
craig.topper added reviewers: evandro, HsiangKai, frasercrmck, khchen, arcbbb.
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As far as I know we're not enforcing the StdExtM must be enabled
to use the V extension. If we use an assert here and hit this
code in a release build we'll silently emit an invalid instruction.

By using a fatal_error we ensure we'll stop the compiler even
in release builds. The error presented to the user won't be the
prettiest, but we won't generate invalid code.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D97970

Files:
  llvm/lib/Target/RISCV/RISCVInstrInfo.cpp


Index: llvm/lib/Target/RISCV/RISCVInstrInfo.cpp
===================================================================
--- llvm/lib/Target/RISCV/RISCVInstrInfo.cpp
+++ llvm/lib/Target/RISCV/RISCVInstrInfo.cpp
@@ -1196,8 +1196,9 @@
     BuildMI(MBB, II, DL, TII->get(RISCV::ADDI), VN)
         .addReg(RISCV::X0)
         .addImm(NumOfVReg);
-    assert(MF.getSubtarget<RISCVSubtarget>().hasStdExtM() &&
-           "M-extension must be enabled to calculate the vscaled size/offset.");
+    if (!MF.getSubtarget<RISCVSubtarget>().hasStdExtM())
+      report_fatal_error("M-extension must be enabled to calculate the vscaled "
+                         "size/offset.");
     BuildMI(MBB, II, DL, TII->get(RISCV::MUL), FactorRegister)
         .addReg(SizeOfVector, RegState::Kill)
         .addReg(VN, RegState::Kill);


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