https://github.com/lukel97 created https://github.com/llvm/llvm-project/pull/79931
This cherry picks a fix 5cf9f2cd9888feea23a624c1de3cc37ce8ce8112 for a miscompile (only with the -mrvv-vector-bits=zvl configuration or similar) introduced in bb8a8770e203ba027d141cd1200e93809ea66c8f, which is present in the 18.x release branch. It also includes a commit that adds a test d407e6ca61a422f25841674d8f0b5ea0dbec85f8 >From 5b3331f29489446d7d723a33310b7fec37153976 Mon Sep 17 00:00:00 2001 From: Luke Lau <l...@igalia.com> Date: Fri, 26 Jan 2024 20:16:21 +0700 Subject: [PATCH 1/2] [RISCV] Add test to showcase miscompile from #79072 --- .../rvv/fixed-vectors-shuffle-exact-vlen.ll | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) diff --git a/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-shuffle-exact-vlen.ll b/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-shuffle-exact-vlen.ll index f53b51e05c572..c0b02f62444ef 100644 --- a/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-shuffle-exact-vlen.ll +++ b/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-shuffle-exact-vlen.ll @@ -138,8 +138,8 @@ define <4 x i64> @m2_splat_two_source(<4 x i64> %v1, <4 x i64> %v2) vscale_range ret <4 x i64> %res } -define <4 x i64> @m2_splat_into_identity_two_source(<4 x i64> %v1, <4 x i64> %v2) vscale_range(2,2) { -; CHECK-LABEL: m2_splat_into_identity_two_source: +define <4 x i64> @m2_splat_into_identity_two_source_v2_hi(<4 x i64> %v1, <4 x i64> %v2) vscale_range(2,2) { +; CHECK-LABEL: m2_splat_into_identity_two_source_v2_hi: ; CHECK: # %bb.0: ; CHECK-NEXT: vsetivli zero, 2, e64, m1, ta, ma ; CHECK-NEXT: vrgather.vi v10, v8, 0 @@ -149,6 +149,20 @@ define <4 x i64> @m2_splat_into_identity_two_source(<4 x i64> %v1, <4 x i64> %v2 ret <4 x i64> %res } +; FIXME: This is a miscompile, we're clobbering the lower reg group of %v2 +; (v10), and the vmv1r.v is moving from the wrong reg group (should be v10) +define <4 x i64> @m2_splat_into_slide_two_source_v2_lo(<4 x i64> %v1, <4 x i64> %v2) vscale_range(2,2) { +; CHECK-LABEL: m2_splat_into_slide_two_source_v2_lo: +; CHECK: # %bb.0: +; CHECK-NEXT: vsetivli zero, 2, e64, m1, ta, ma +; CHECK-NEXT: vrgather.vi v10, v8, 0 +; CHECK-NEXT: vmv1r.v v11, v8 +; CHECK-NEXT: vmv2r.v v8, v10 +; CHECK-NEXT: ret + %res = shufflevector <4 x i64> %v1, <4 x i64> %v2, <4 x i32> <i32 0, i32 0, i32 4, i32 5> + ret <4 x i64> %res +} + define <4 x i64> @m2_splat_into_slide_two_source(<4 x i64> %v1, <4 x i64> %v2) vscale_range(2,2) { ; CHECK-LABEL: m2_splat_into_slide_two_source: ; CHECK: # %bb.0: >From 60341586c8bd46b1094663749ac6467058b7efe8 Mon Sep 17 00:00:00 2001 From: Luke Lau <l...@igalia.com> Date: Fri, 26 Jan 2024 20:18:08 +0700 Subject: [PATCH 2/2] [RISCV] Fix M1 shuffle on wrong SrcVec in lowerShuffleViaVRegSplitting This fixes a miscompile from #79072 where we were taking the wrong SrcVec to do the M1 shuffle. E.g. if the SrcVecIdx was 2 and we had 2 VRegsPerSrc, we ended up taking it from V1 instead of V2. --- llvm/lib/Target/RISCV/RISCVISelLowering.cpp | 2 +- .../CodeGen/RISCV/rvv/fixed-vectors-shuffle-exact-vlen.ll | 8 +++----- 2 files changed, 4 insertions(+), 6 deletions(-) diff --git a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp index 47c6cd6e5487b..7895d74f06d12 100644 --- a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp +++ b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp @@ -4718,7 +4718,7 @@ static SDValue lowerShuffleViaVRegSplitting(ShuffleVectorSDNode *SVN, if (SrcVecIdx == -1) continue; unsigned ExtractIdx = (SrcVecIdx % VRegsPerSrc) * NumOpElts; - SDValue SrcVec = (unsigned)SrcVecIdx > VRegsPerSrc ? V2 : V1; + SDValue SrcVec = (unsigned)SrcVecIdx >= VRegsPerSrc ? V2 : V1; SDValue SubVec = DAG.getNode(ISD::EXTRACT_SUBVECTOR, DL, M1VT, SrcVec, DAG.getVectorIdxConstant(ExtractIdx, DL)); SubVec = convertFromScalableVector(OneRegVT, SubVec, DAG, Subtarget); diff --git a/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-shuffle-exact-vlen.ll b/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-shuffle-exact-vlen.ll index c0b02f62444ef..3f0bdb9d5e316 100644 --- a/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-shuffle-exact-vlen.ll +++ b/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-shuffle-exact-vlen.ll @@ -149,15 +149,13 @@ define <4 x i64> @m2_splat_into_identity_two_source_v2_hi(<4 x i64> %v1, <4 x i6 ret <4 x i64> %res } -; FIXME: This is a miscompile, we're clobbering the lower reg group of %v2 -; (v10), and the vmv1r.v is moving from the wrong reg group (should be v10) define <4 x i64> @m2_splat_into_slide_two_source_v2_lo(<4 x i64> %v1, <4 x i64> %v2) vscale_range(2,2) { ; CHECK-LABEL: m2_splat_into_slide_two_source_v2_lo: ; CHECK: # %bb.0: ; CHECK-NEXT: vsetivli zero, 2, e64, m1, ta, ma -; CHECK-NEXT: vrgather.vi v10, v8, 0 -; CHECK-NEXT: vmv1r.v v11, v8 -; CHECK-NEXT: vmv2r.v v8, v10 +; CHECK-NEXT: vrgather.vi v12, v8, 0 +; CHECK-NEXT: vmv1r.v v13, v10 +; CHECK-NEXT: vmv2r.v v8, v12 ; CHECK-NEXT: ret %res = shufflevector <4 x i64> %v1, <4 x i64> %v2, <4 x i32> <i32 0, i32 0, i32 4, i32 5> ret <4 x i64> %res _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits