[llvm] 04977ce - [RISCV] Fix a crash in fixed-length build_vector lowering

[Fraser Cormack via llvm-commits]

Author: Fraser Cormack
Date: 2021-02-16T10:25:15Z
New Revision: 04977ce5ce1ba9646baa75f1fb91af5d518a121e

URL: https://github.com/llvm/llvm-project/commit/04977ce5ce1ba9646baa75f1fb91af5d518a121e
DIFF: https://github.com/llvm/llvm-project/commit/04977ce5ce1ba9646baa75f1fb91af5d518a121e.diff

LOG: [RISCV] Fix a crash in fixed-length build_vector lowering

Non-splatted non-integer build_vector nodes were mistakenly being
lowered as VID expressions, which should not happen. VID can only be
used to select integer build_vector nodes.

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D96718

Added: 
    llvm/test/CodeGen/RISCV/rvv/fixed-vectors-fp-buildvec.ll

Modified: 
    llvm/lib/Target/RISCV/RISCVISelLowering.cpp

Removed: 
    


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diff  --git a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
index e77224648bfc..f7b7fc8510b0 100644
--- a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
+++ b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -901,16 +901,17 @@ static SDValue lowerBUILD_VECTOR(SDValue Op, SelectionDAG &DAG,
 
   // Try and match an index sequence, which we can lower directly to the vid
   // instruction. An all-undef vector is matched by getSplatValue, above.
-  bool IsVID = true;
-  if (VT.isInteger())
+  if (VT.isInteger()) {
+    bool IsVID = true;
     for (unsigned i = 0, e = Op.getNumOperands(); i < e && IsVID; i++)
       IsVID &= Op.getOperand(i).isUndef() ||
                (isa<ConstantSDNode>(Op.getOperand(i)) &&
                 Op.getConstantOperandVal(i) == i);
 
-  if (IsVID) {
-    SDValue VID = DAG.getNode(RISCVISD::VID_VL, DL, ContainerVT, Mask, VL);
-    return convertFromScalableVector(VT, VID, DAG, Subtarget);
+    if (IsVID) {
+      SDValue VID = DAG.getNode(RISCVISD::VID_VL, DL, ContainerVT, Mask, VL);
+      return convertFromScalableVector(VT, VID, DAG, Subtarget);
+    }
   }
 
   return SDValue();

diff  --git a/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-fp-buildvec.ll b/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-fp-buildvec.ll
new file mode 100644
index 000000000000..f1133f59382c
--- /dev/null
+++ b/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-fp-buildvec.ll
@@ -0,0 +1,22 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+
+; RUN: llc -mtriple=riscv32 -target-abi=ilp32d -mattr=+experimental-v,+experimental-zfh,+f,+d -verify-machineinstrs -riscv-v-vector-bits-min=128 -riscv-v-fixed-length-vector-lmul-max=2 -verify-machineinstrs < %s | FileCheck %s --check-prefixes=CHECK,LMULMAX2
+; RUN: llc -mtriple=riscv64 -target-abi=lp64d -mattr=+experimental-v,+experimental-zfh,+f,+d -verify-machineinstrs -riscv-v-vector-bits-min=128 -riscv-v-fixed-length-vector-lmul-max=2 -verify-machineinstrs < %s | FileCheck %s --check-prefixes=CHECK,LMULMAX2
+; RUN: llc -mtriple=riscv32 -target-abi=ilp32d -mattr=+experimental-v,+experimental-zfh,+f,+d -verify-machineinstrs -riscv-v-vector-bits-min=128 -riscv-v-fixed-length-vector-lmul-max=1 -verify-machineinstrs < %s | FileCheck %s --check-prefixes=CHECK,LMULMAX1
+; RUN: llc -mtriple=riscv64 -target-abi=lp64d -mattr=+experimental-v,+experimental-zfh,+f,+d -verify-machineinstrs -riscv-v-vector-bits-min=128 -riscv-v-fixed-length-vector-lmul-max=1 -verify-machineinstrs < %s | FileCheck %s --check-prefixes=CHECK,LMULMAX1
+
+; Tests that a floating-point build_vector doesn't try and generate a VID
+; instruction
+define void @buildvec_no_vid_v4f32(<4 x float>* %x) {
+; CHECK-LABEL: buildvec_no_vid_v4f32:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    lui a1, %hi(.LCPI0_0)
+; CHECK-NEXT:    addi a1, a1, %lo(.LCPI0_0)
+; CHECK-NEXT:    addi a2, zero, 4
+; CHECK-NEXT:    vsetvli a2, a2, e32,m1,ta,mu
+; CHECK-NEXT:    vle32.v v25, (a1)
+; CHECK-NEXT:    vse32.v v25, (a0)
+; CHECK-NEXT:    ret
+  store <4 x float> <float 0.0, float 4.0, float 0.0, float 2.0>, <4 x float>* %x
+  ret void
+}