[llvm] Revert "DAG: Preserve range metadata when load is narrowed" (PR #128948)
Daniel Thornburgh via llvm-commits
llvm-commits at lists.llvm.org
Wed Feb 26 14:01:03 PST 2025
https://github.com/mysterymath created https://github.com/llvm/llvm-project/pull/128948
Reverts llvm/llvm-project#128144
Breaks clang prod x64 build (seen in Fuchsia toolchain)
>From c788a84fdd2316daa0204a13bdf93a503b95cabf Mon Sep 17 00:00:00 2001
From: Daniel Thornburgh <mysterymath at gmail.com>
Date: Wed, 26 Feb 2025 14:00:23 -0800
Subject: [PATCH] Revert "DAG: Preserve range metadata when load is narrowed
(#128144)"
This reverts commit d8bcb53780bf8e2f622380d5f4ccde96fa1d81a9.
---
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 29 ++-------
llvm/test/CodeGen/AMDGPU/shl64_reduce.ll | 64 +++----------------
2 files changed, 14 insertions(+), 79 deletions(-)
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index de7d9e28bb93a..f197ae61550a9 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -14903,29 +14903,12 @@ SDValue DAGCombiner::reduceLoadWidth(SDNode *N) {
AddToWorklist(NewPtr.getNode());
SDValue Load;
- if (ExtType == ISD::NON_EXTLOAD) {
- const MDNode *OldRanges = LN0->getRanges();
- const MDNode *NewRanges = nullptr;
- // If LSBs are loaded and the truncated ConstantRange for the OldRanges
- // metadata is not the full-set for the NewWidth then create a NewRanges
- // metadata for the truncated load
- if (ShAmt == 0 && OldRanges) {
- ConstantRange CR = getConstantRangeFromMetadata(*OldRanges);
- ConstantRange TruncatedCR = CR.truncate(VT.getScalarSizeInBits());
-
- if (!TruncatedCR.isFullSet()) {
- Metadata *Bounds[2] = {ConstantAsMetadata::get(ConstantInt::get(
- *DAG.getContext(), TruncatedCR.getLower())),
- ConstantAsMetadata::get(ConstantInt::get(
- *DAG.getContext(), TruncatedCR.getUpper()))};
- NewRanges = MDNode::get(*DAG.getContext(), Bounds);
- }
- }
- Load = DAG.getLoad(
- VT, DL, LN0->getChain(), NewPtr,
- LN0->getPointerInfo().getWithOffset(PtrOff), LN0->getOriginalAlign(),
- LN0->getMemOperand()->getFlags(), LN0->getAAInfo(), NewRanges);
- } else
+ if (ExtType == ISD::NON_EXTLOAD)
+ Load = DAG.getLoad(VT, DL, LN0->getChain(), NewPtr,
+ LN0->getPointerInfo().getWithOffset(PtrOff),
+ LN0->getOriginalAlign(),
+ LN0->getMemOperand()->getFlags(), LN0->getAAInfo());
+ else
Load = DAG.getExtLoad(ExtType, DL, VT, LN0->getChain(), NewPtr,
LN0->getPointerInfo().getWithOffset(PtrOff), ExtVT,
LN0->getOriginalAlign(),
diff --git a/llvm/test/CodeGen/AMDGPU/shl64_reduce.ll b/llvm/test/CodeGen/AMDGPU/shl64_reduce.ll
index 69242f4e44840..05430213c17d2 100644
--- a/llvm/test/CodeGen/AMDGPU/shl64_reduce.ll
+++ b/llvm/test/CodeGen/AMDGPU/shl64_reduce.ll
@@ -13,66 +13,23 @@
; Test range with metadata
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; FIXME: This case should be reduced, but SelectionDAG::computeKnownBits() cannot
+; determine the minimum from metadata in this case. Match current results
+; for now.
+
define i64 @shl_metadata(i64 %arg0, ptr %arg1.ptr) {
; CHECK-LABEL: shl_metadata:
; CHECK: ; %bb.0:
; CHECK-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
-; CHECK-NEXT: flat_load_dword v1, v[2:3]
-; CHECK-NEXT: s_waitcnt vmcnt(0) lgkmcnt(0)
-; CHECK-NEXT: v_lshlrev_b32_e32 v1, v1, v0
-; CHECK-NEXT: v_mov_b32_e32 v0, 0
-; CHECK-NEXT: s_setpc_b64 s[30:31]
- %shift.amt = load i64, ptr %arg1.ptr, !range !0, !noundef !{}
- %shl = shl i64 %arg0, %shift.amt
- ret i64 %shl
-}
-
-define i64 @shl_metadata_two_ranges(i64 %arg0, ptr %arg1.ptr) {
-; CHECK-LABEL: shl_metadata_two_ranges:
-; CHECK: ; %bb.0:
-; CHECK-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
-; CHECK-NEXT: flat_load_dword v1, v[2:3]
-; CHECK-NEXT: s_waitcnt vmcnt(0) lgkmcnt(0)
-; CHECK-NEXT: v_lshlrev_b32_e32 v1, v1, v0
-; CHECK-NEXT: v_mov_b32_e32 v0, 0
-; CHECK-NEXT: s_setpc_b64 s[30:31]
- %shift.amt = load i64, ptr %arg1.ptr, !range !1, !noundef !{}
- %shl = shl i64 %arg0, %shift.amt
- ret i64 %shl
-}
-
-; Known minimum is too low. Reduction must not be done.
-define i64 @shl_metadata_out_of_range(i64 %arg0, ptr %arg1.ptr) {
-; CHECK-LABEL: shl_metadata_out_of_range:
-; CHECK: ; %bb.0:
-; CHECK-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
-; CHECK-NEXT: flat_load_dword v2, v[2:3]
-; CHECK-NEXT: s_waitcnt vmcnt(0) lgkmcnt(0)
-; CHECK-NEXT: v_lshlrev_b64 v[0:1], v2, v[0:1]
-; CHECK-NEXT: s_setpc_b64 s[30:31]
- %shift.amt = load i64, ptr %arg1.ptr, !range !2, !noundef !{}
- %shl = shl i64 %arg0, %shift.amt
- ret i64 %shl
-}
-
-; Bounds cannot be truncated to i32 when load is narrowed to i32.
-; Reduction must not be done.
-; Bounds were chosen so that if bounds were truncated to i32 the
-; known minimum would be 32 and the shl would be erroneously reduced.
-define i64 @shl_metadata_cant_be_narrowed_to_i32(i64 %arg0, ptr %arg1.ptr) {
-; CHECK-LABEL: shl_metadata_cant_be_narrowed_to_i32:
-; CHECK: ; %bb.0:
-; CHECK-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
; CHECK-NEXT: flat_load_dword v2, v[2:3]
; CHECK-NEXT: s_waitcnt vmcnt(0) lgkmcnt(0)
; CHECK-NEXT: v_lshlrev_b64 v[0:1], v2, v[0:1]
; CHECK-NEXT: s_setpc_b64 s[30:31]
- %shift.amt = load i64, ptr %arg1.ptr, !range !3, !noundef !{}
+ %shift.amt = load i64, ptr %arg1.ptr, !range !0
%shl = shl i64 %arg0, %shift.amt
ret i64 %shl
}
-; FIXME: This case should be reduced
define <2 x i64> @shl_v2_metadata(<2 x i64> %arg0, ptr %arg1.ptr) {
; CHECK-LABEL: shl_v2_metadata:
; CHECK: ; %bb.0:
@@ -82,12 +39,11 @@ define <2 x i64> @shl_v2_metadata(<2 x i64> %arg0, ptr %arg1.ptr) {
; CHECK-NEXT: v_lshlrev_b64 v[0:1], v4, v[0:1]
; CHECK-NEXT: v_lshlrev_b64 v[2:3], v6, v[2:3]
; CHECK-NEXT: s_setpc_b64 s[30:31]
- %shift.amt = load <2 x i64>, ptr %arg1.ptr, !range !0, !noundef !{}
+ %shift.amt = load <2 x i64>, ptr %arg1.ptr, !range !0
%shl = shl <2 x i64> %arg0, %shift.amt
ret <2 x i64> %shl
}
-; FIXME: This case should be reduced
define <3 x i64> @shl_v3_metadata(<3 x i64> %arg0, ptr %arg1.ptr) {
; CHECK-LABEL: shl_v3_metadata:
; CHECK: ; %bb.0:
@@ -99,12 +55,11 @@ define <3 x i64> @shl_v3_metadata(<3 x i64> %arg0, ptr %arg1.ptr) {
; CHECK-NEXT: v_lshlrev_b64 v[0:1], v8, v[0:1]
; CHECK-NEXT: v_lshlrev_b64 v[2:3], v10, v[2:3]
; CHECK-NEXT: s_setpc_b64 s[30:31]
- %shift.amt = load <3 x i64>, ptr %arg1.ptr, !range !0, !noundef !{}
+ %shift.amt = load <3 x i64>, ptr %arg1.ptr, !range !0
%shl = shl <3 x i64> %arg0, %shift.amt
ret <3 x i64> %shl
}
-; FIXME: This case should be reduced
define <4 x i64> @shl_v4_metadata(<4 x i64> %arg0, ptr %arg1.ptr) {
; CHECK-LABEL: shl_v4_metadata:
; CHECK: ; %bb.0:
@@ -119,15 +74,12 @@ define <4 x i64> @shl_v4_metadata(<4 x i64> %arg0, ptr %arg1.ptr) {
; CHECK-NEXT: v_lshlrev_b64 v[4:5], v13, v[4:5]
; CHECK-NEXT: v_lshlrev_b64 v[6:7], v15, v[6:7]
; CHECK-NEXT: s_setpc_b64 s[30:31]
- %shift.amt = load <4 x i64>, ptr %arg1.ptr, !range !0, !noundef !{}
+ %shift.amt = load <4 x i64>, ptr %arg1.ptr, !range !0
%shl = shl <4 x i64> %arg0, %shift.amt
ret <4 x i64> %shl
}
!0 = !{i64 32, i64 64}
-!1 = !{i64 32, i64 38, i64 42, i64 48}
-!2 = !{i64 31, i64 38, i64 42, i64 48}
-!3 = !{i64 32, i64 38, i64 2147483680, i64 2147483681}
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Test range with an "or X, 16"
More information about the llvm-commits
mailing list