[llvm] r328508 - [Pipeliner] Correctly update memoperands in the epilog
Krzysztof Parzyszek via llvm-commits
llvm-commits at lists.llvm.org
Mon Mar 26 08:45:55 PDT 2018
Author: kparzysz
Date: Mon Mar 26 08:45:55 2018
New Revision: 328508
URL: http://llvm.org/viewvc/llvm-project?rev=328508&view=rev
Log:
[Pipeliner] Correctly update memoperands in the epilog
The pipeliner needs to be conservative when updating the memoperands
of instructions in the epilog. Previously, the pipeliner was changing
the offset of the memoperand based upon the scheduling stage. However,
that is incorrect when control flow branches around the kernel code.
The bug enabled a load and store to the same stack offset to be swapped.
This patch fixes the bug by updating the size of the memoperands to be
UINT_MAX. This conservative value means that dependences will be created
between other loads and stores.
Patch by Brendon Cahoon.
Added:
llvm/trunk/test/CodeGen/Hexagon/swp-memrefs-epilog.ll
Modified:
llvm/trunk/lib/CodeGen/MachinePipeliner.cpp
Modified: llvm/trunk/lib/CodeGen/MachinePipeliner.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/MachinePipeliner.cpp?rev=328508&r1=328507&r2=328508&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/MachinePipeliner.cpp (original)
+++ llvm/trunk/lib/CodeGen/MachinePipeliner.cpp Mon Mar 26 08:45:55 2018
@@ -2489,7 +2489,9 @@ void SwingSchedulerDAG::generateEpilog(S
continue;
MachineInstr *In = &BBI;
if (Schedule.isScheduledAtStage(getSUnit(In), StageNum)) {
- MachineInstr *NewMI = cloneInstr(In, EpilogStage - LastStage, 0);
+ // Instructions with memoperands in the epilog are updated with
+ // conservative values.
+ MachineInstr *NewMI = cloneInstr(In, UINT_MAX, 0);
updateInstruction(NewMI, i == 1, EpilogStage, 0, Schedule, VRMap);
NewBB->push_back(NewMI);
InstrMap[NewMI] = In;
@@ -3157,7 +3159,7 @@ void SwingSchedulerDAG::updateMemOperand
continue;
}
unsigned Delta;
- if (computeDelta(OldMI, Delta)) {
+ if (Num != UINT_MAX && computeDelta(OldMI, Delta)) {
int64_t AdjOffset = Delta * Num;
NewMemRefs[Refs++] =
MF.getMachineMemOperand(MMO, AdjOffset, MMO->getSize());
Added: llvm/trunk/test/CodeGen/Hexagon/swp-memrefs-epilog.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/Hexagon/swp-memrefs-epilog.ll?rev=328508&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/Hexagon/swp-memrefs-epilog.ll (added)
+++ llvm/trunk/test/CodeGen/Hexagon/swp-memrefs-epilog.ll Mon Mar 26 08:45:55 2018
@@ -0,0 +1,102 @@
+; RUN: llc -march=hexagon -O2 -fp-contract=fast < %s | FileCheck %s
+
+; Test that the memoperands for instructions in the epilog are updated
+; correctly. Previously, the pipeliner updated the offset for the memoperands
+; in the epilog. But, the value of the offset is incorrect when control flow
+; branches around the kernel.
+
+; In this test, we check that a load and store to the same location are not
+; swapped due to a bad offset in the memoperands. The store and load are both
+; to r29+32. If the memoperands are updated incorrectly, these are swapped.
+
+; CHECK: [[REG0:r([0-9]+)]] = add(r29,#24)
+; CHECK: [[REG1:r([0-9]+)]] = add([[REG0]],#4)
+; CHECK: memw([[REG1]]+#{{[0-9]}}) = r{{[0-9]+}}
+; CHECK: r{{[0-9]+}} = memw(r29+#{{[0-9]+}})
+
+%s.0 = type { %s.1 }
+%s.1 = type { %s.2 }
+%s.2 = type { %s.3 }
+%s.3 = type { [9 x float] }
+%s.4 = type { %s.5 }
+%s.5 = type { %s.6 }
+%s.6 = type { %s.7 }
+%s.7 = type { [3 x float] }
+
+ at g0 = external hidden unnamed_addr constant [29 x i8], align 1
+
+define i32 @f0() unnamed_addr {
+b0:
+ %v0 = alloca %s.0, align 4
+ %v1 = alloca %s.4, align 4
+ %v2 = bitcast %s.0* %v0 to i8*
+ call void @llvm.lifetime.start.p0i8(i64 36, i8* %v2)
+ %v3 = getelementptr inbounds %s.0, %s.0* %v0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 0
+ store float 0x3FEFFF7160000000, float* %v3, align 4
+ %v4 = getelementptr inbounds %s.0, %s.0* %v0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 1
+ store float 0xBF87867F00000000, float* %v4, align 4
+ %v5 = getelementptr inbounds %s.0, %s.0* %v0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 2
+ store float 0xBF6185CEE0000000, float* %v5, align 4
+ %v6 = getelementptr inbounds %s.0, %s.0* %v0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 3
+ store float 0x3F8780BAA0000000, float* %v6, align 4
+ %v7 = getelementptr inbounds %s.0, %s.0* %v0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 4
+ store float 0x3FEFFF5C60000000, float* %v7, align 4
+ %v8 = getelementptr inbounds %s.0, %s.0* %v0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 5
+ store float 0xBF74717160000000, float* %v8, align 4
+ %v9 = getelementptr inbounds %s.0, %s.0* %v0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 6
+ store float 0x3F61FF7160000000, float* %v9, align 4
+ %v10 = getelementptr inbounds %s.0, %s.0* %v0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 7
+ store float 0x3F74573A80000000, float* %v10, align 4
+ %v11 = getelementptr inbounds %s.0, %s.0* %v0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 8
+ store float 0x3FEFFFE080000000, float* %v11, align 4
+ %v12 = bitcast %s.4* %v1 to i8*
+ call void @llvm.lifetime.start.p0i8(i64 12, i8* %v12)
+ br label %b1
+
+b1: ; preds = %b1, %b0
+ %v13 = phi i32 [ 0, %b0 ], [ %v29, %b1 ]
+ %v14 = mul nuw nsw i32 %v13, 3
+ %v15 = getelementptr inbounds %s.0, %s.0* %v0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 %v14
+ %v16 = load float, float* %v15, align 4
+ %v17 = fmul float %v16, 0x3FE7B2B120000000
+ %v18 = add nuw nsw i32 %v14, 1
+ %v19 = getelementptr inbounds %s.0, %s.0* %v0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 %v18
+ %v20 = load float, float* %v19, align 4
+ %v21 = fmul float %v20, 0x3FDA8BC9C0000000
+ %v22 = fsub float %v21, %v17
+ %v23 = add nuw nsw i32 %v14, 2
+ %v24 = getelementptr inbounds %s.0, %s.0* %v0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 %v23
+ %v25 = load float, float* %v24, align 4
+ %v26 = fmul float %v25, 0x40030D6700000000
+ %v27 = fadd float %v22, %v26
+ %v28 = getelementptr inbounds %s.4, %s.4* %v1, i32 0, i32 0, i32 0, i32 0, i32 0, i32 %v13
+ store float %v27, float* %v28, align 4
+ %v29 = add nuw nsw i32 %v13, 1
+ %v30 = icmp eq i32 %v29, 3
+ br i1 %v30, label %b2, label %b1
+
+b2: ; preds = %b1
+ %v31 = getelementptr inbounds %s.4, %s.4* %v1, i32 0, i32 0, i32 0, i32 0, i32 0, i32 0
+ %v32 = load float, float* %v31, align 4
+ %v33 = fpext float %v32 to double
+ %v34 = getelementptr inbounds %s.4, %s.4* %v1, i32 0, i32 0, i32 0, i32 0, i32 0, i32 1
+ %v35 = load float, float* %v34, align 4
+ %v36 = fpext float %v35 to double
+ %v37 = getelementptr inbounds %s.4, %s.4* %v1, i32 0, i32 0, i32 0, i32 0, i32 0, i32 2
+ %v38 = load float, float* %v37, align 4
+ %v39 = fpext float %v38 to double
+ %v40 = tail call i32 (i8*, ...) @f1(i8* getelementptr inbounds ([29 x i8], [29 x i8]* @g0, i32 0, i32 0), double %v33, double %v36, double %v39)
+ call void @llvm.lifetime.end.p0i8(i64 12, i8* nonnull %v12)
+ call void @llvm.lifetime.end.p0i8(i64 36, i8* nonnull %v2)
+ ret i32 0
+}
+
+declare i32 @f1(i8* nocapture readonly, ...) local_unnamed_addr
+
+; Function Attrs: argmemonly nounwind
+declare void @llvm.lifetime.start.p0i8(i64, i8* nocapture) #0
+
+; Function Attrs: argmemonly nounwind
+declare void @llvm.lifetime.end.p0i8(i64, i8* nocapture) #0
+
+attributes #0 = { argmemonly nounwind }
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