[llvm] cdc633e - Revert "TargetLowering: fix an infinite DAG combine in SimplifySETCC"
Jon Roelofs via llvm-commits
llvm-commits at lists.llvm.org
Wed Jul 12 12:22:17 PDT 2023
Author: Jon Roelofs
Date: 2023-07-12T12:22:03-07:00
New Revision: cdc633e4bc93d4bf241ecd4c29691ae065749313
URL: https://github.com/llvm/llvm-project/commit/cdc633e4bc93d4bf241ecd4c29691ae065749313
DIFF: https://github.com/llvm/llvm-project/commit/cdc633e4bc93d4bf241ecd4c29691ae065749313.diff
LOG: Revert "TargetLowering: fix an infinite DAG combine in SimplifySETCC"
This reverts commit b76c85b355578d9076c22a86faf4ea8de1745bdf.
It broke the RISCV-enabled bots. Oops.
Added:
Modified:
llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
Removed:
llvm/test/CodeGen/AArch64/arm64-setcc-swap-infloop.ll
################################################################################
diff --git a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
index 19a3cb1439baee..e2903efdfacc1a 100644
--- a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -4227,12 +4227,12 @@ SDValue TargetLowering::SimplifySetCC(EVT VT, SDValue N0, SDValue N1,
bool N1ConstOrSplat =
isConstOrConstSplat(N1, /*AllowUndefs*/ false, /*AllowTruncate*/ true);
- // Canonicalize toward having the constant on the RHS.
+ // Ensure that the constant occurs on the RHS and fold constant comparisons.
// TODO: Handle non-splat vector constants. All undef causes trouble.
// FIXME: We can't yet fold constant scalable vector splats, so avoid an
// infinite loop here when we encounter one.
ISD::CondCode SwappedCC = ISD::getSetCCSwappedOperands(Cond);
- if (N0ConstOrSplat && !N1ConstOrSplat && !OpVT.isScalableVector() &&
+ if (N0ConstOrSplat && (!OpVT.isScalableVector() || !N1ConstOrSplat) &&
(DCI.isBeforeLegalizeOps() ||
isCondCodeLegal(SwappedCC, N0.getSimpleValueType())))
return DAG.getSetCC(dl, VT, N1, N0, SwappedCC);
diff --git a/llvm/test/CodeGen/AArch64/arm64-setcc-swap-infloop.ll b/llvm/test/CodeGen/AArch64/arm64-setcc-swap-infloop.ll
deleted file mode 100644
index e2c5546ab42330..00000000000000
--- a/llvm/test/CodeGen/AArch64/arm64-setcc-swap-infloop.ll
+++ /dev/null
@@ -1,33 +0,0 @@
-; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
-; RUN: llc < %s -mtriple=arm64-apple-ios --global-isel=0 | FileCheck %s
-
-target datalayout = "e-m:o-i64:64-i128:128-n32:64-S128"
-target triple = "arm64-apple-ios"
-
-declare void @llvm.memset.p0.i64(ptr nocapture writeonly, i8, i64, i1 immarg)
-
-; TargetLowering::SimplifySetCC wants to swap the operands of a SETCC to
-; canonicalize the constant to the RHS. The bug here was that it did so whether
-; or not the RHS was already a constant, leading to an infinite loop.
-define <16 x i1> @setcc_swap_infloop(ptr %arg) {
-; CHECK-LABEL: setcc_swap_infloop:
-; CHECK: ; %bb.0:
-; CHECK-NEXT: mov x8, xzr
-; CHECK-NEXT: mov w9, #16 ; =0x10
-; CHECK-NEXT: movi.16b v1, #1
-; CHECK-NEXT: ldr q0, [x8]
-; CHECK-NEXT: cmeq.16b v2, v1, #0
-; CHECK-NEXT: str q1, [x8]
-; CHECK-NEXT: cmeq.16b v0, v0, #0
-; CHECK-NEXT: str q1, [x9]
-; CHECK-NEXT: orr.16b v0, v0, v2
-; CHECK-NEXT: ret
- call void @llvm.memset.p0.i64(ptr nonnull null, i8 1, i64 32, i1 false)
- %v = getelementptr inbounds i8, ptr null, i64 16
- %v14 = load <16 x i8>, ptr undef, align 32
- %v15 = icmp eq <16 x i8> %v14, zeroinitializer
- %v16 = load <16 x i8>, ptr %v, align 16
- %v17 = icmp eq <16 x i8> %v16, zeroinitializer
- %v20 = or <16 x i1> %v15, %v17
- ret <16 x i1> %v20
-}
More information about the llvm-commits
mailing list