[llvm-branch-commits] [llvm] 908c1ba - [RISCV] Fix incorrect extend type in vwmulsu combine.

[Tom Stellard via llvm-branch-commits]

Author: Craig Topper
Date: 2022-02-21T11:20:52-08:00
New Revision: 908c1bae6e7fa2339e8b9b7856d849f20e98f653

URL: https://github.com/llvm/llvm-project/commit/908c1bae6e7fa2339e8b9b7856d849f20e98f653
DIFF: https://github.com/llvm/llvm-project/commit/908c1bae6e7fa2339e8b9b7856d849f20e98f653.diff

LOG: [RISCV] Fix incorrect extend type in vwmulsu combine.

While matching widening multiply, if we matched an extend from i8->i32,
i16->i64 or i8->i64, we need to reintroduce a narrower extend. If we're
matching a vwmulsu we need to use a sext for op0 and a zext for op1.

This bug exists in LLVM 14 and will need to be backported.

Differential Revision: https://reviews.llvm.org/D119618

(cherry picked from commit 478c237e21b2c3a83e46f26fcbeb3876682f9b14)

Added: 
    

Modified: 
    llvm/lib/Target/RISCV/RISCVISelLowering.cpp
    llvm/test/CodeGen/RISCV/rvv/fixed-vectors-vwmulsu.ll

Removed: 
    


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diff  --git a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
index 97d24c8e9c0b..2fe491ad5ea4 100644
--- a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
+++ b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -7443,6 +7443,8 @@ static SDValue combineMUL_VLToVWMUL_VL(SDNode *N, SelectionDAG &DAG,
   unsigned ExtOpc = IsSignExt ? RISCVISD::VSEXT_VL : RISCVISD::VZEXT_VL;
   if (Op0.getValueType() != NarrowVT)
     Op0 = DAG.getNode(ExtOpc, DL, NarrowVT, Op0, Mask, VL);
+  // vwmulsu requires second operand to be zero extended.
+  ExtOpc = IsVWMULSU ? RISCVISD::VZEXT_VL : ExtOpc;
   if (Op1.getValueType() != NarrowVT)
     Op1 = DAG.getNode(ExtOpc, DL, NarrowVT, Op1, Mask, VL);
 

diff  --git a/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-vwmulsu.ll b/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-vwmulsu.ll
index 6c204b24ae2b..ffe4c5613090 100644
--- a/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-vwmulsu.ll
+++ b/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-vwmulsu.ll
@@ -375,7 +375,7 @@ define <2 x i32> @vwmulsu_v2i32_v2i8(<2 x i8>* %x, <2 x i8>* %y) {
 ; CHECK-NEXT:    vle8.v v8, (a0)
 ; CHECK-NEXT:    vle8.v v9, (a1)
 ; CHECK-NEXT:    vsetvli zero, zero, e16, mf4, ta, mu
-; CHECK-NEXT:    vsext.vf2 v10, v8
+; CHECK-NEXT:    vzext.vf2 v10, v8
 ; CHECK-NEXT:    vsext.vf2 v11, v9
 ; CHECK-NEXT:    vwmulsu.vv v8, v11, v10
 ; CHECK-NEXT:    ret
@@ -394,7 +394,7 @@ define <4 x i32> @vwmulsu_v4i32_v4i8_v4i16(<4 x i8>* %x, <4 x i16>* %y) {
 ; CHECK-NEXT:    vle8.v v8, (a0)
 ; CHECK-NEXT:    vle16.v v9, (a1)
 ; CHECK-NEXT:    vsetvli zero, zero, e16, mf2, ta, mu
-; CHECK-NEXT:    vsext.vf2 v10, v8
+; CHECK-NEXT:    vzext.vf2 v10, v8
 ; CHECK-NEXT:    vwmulsu.vv v8, v9, v10
 ; CHECK-NEXT:    ret
   %a = load <4 x i8>, <4 x i8>* %x