851a7caf1a
* gnu/packages/llvm.scm (llvm-9)[source]: Add new patches. * gnu/packages/patches/llvm-9-fix-lpad-miscompilation.patch, gnu/packages/patches/llvm-9-fix-scev-miscompilation.patch: New files. * gnu/local.mk (dist_patch_DATA): Register new patches.
97 lines
3.5 KiB
Diff
97 lines
3.5 KiB
Diff
From 011fb5bf8b31316472fccb1a19c91912246df9b2 Mon Sep 17 00:00:00 2001
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From: Reid Kleckner <rnk@google.com>
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Date: Sat, 28 Mar 2020 11:03:14 -0700
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Subject: [PATCH] [CodeGen] Fix sinking local values in lpads with phis
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There was already a test case for landingpads to handle this case, but I
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had forgotten to consider PHI instructions preceding the EH_LABEL in the
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landingpad.
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PR45261
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---
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llvm/lib/CodeGen/SelectionDAG/FastISel.cpp | 17 +++++++++-
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llvm/test/CodeGen/X86/sink-local-value.ll | 36 ++++++++++++++++++++++
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2 files changed, 52 insertions(+), 1 deletion(-)
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diff --git a/llvm/lib/CodeGen/SelectionDAG/FastISel.cpp b/llvm/lib/CodeGen/SelectionDAG/FastISel.cpp
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index 5ac3606dc662..2638b1e8a05c 100644
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--- a/llvm/lib/CodeGen/SelectionDAG/FastISel.cpp
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+++ b/llvm/lib/CodeGen/SelectionDAG/FastISel.cpp
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@@ -225,6 +225,21 @@ static bool isRegUsedByPhiNodes(unsigned DefReg,
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return false;
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}
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+static bool isTerminatingEHLabel(MachineBasicBlock *MBB, MachineInstr &MI) {
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+ // Ignore non-EH labels.
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+ if (!MI.isEHLabel())
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+ return false;
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+
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+ // Any EH label outside a landing pad must be for an invoke. Consider it a
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+ // terminator.
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+ if (!MBB->isEHPad())
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+ return true;
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+
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+ // If this is a landingpad, the first non-phi instruction will be an EH_LABEL.
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+ // Don't consider that label to be a terminator.
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+ return MI.getIterator() != MBB->getFirstNonPHI();
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+}
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+
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/// Build a map of instruction orders. Return the first terminator and its
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/// order. Consider EH_LABEL instructions to be terminators as well, since local
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/// values for phis after invokes must be materialized before the call.
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@@ -233,7 +248,7 @@ void FastISel::InstOrderMap::initialize(
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unsigned Order = 0;
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for (MachineInstr &I : *MBB) {
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if (!FirstTerminator &&
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- (I.isTerminator() || (I.isEHLabel() && &I != &MBB->front()))) {
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+ (I.isTerminator() || isTerminatingEHLabel(MBB, I))) {
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FirstTerminator = &I;
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FirstTerminatorOrder = Order;
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}
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diff --git a/llvm/test/CodeGen/X86/sink-local-value.ll b/llvm/test/CodeGen/X86/sink-local-value.ll
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index b0e511ac1189..f7d861ac9b6c 100644
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--- a/llvm/test/CodeGen/X86/sink-local-value.ll
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+++ b/llvm/test/CodeGen/X86/sink-local-value.ll
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@@ -145,6 +145,42 @@ try.cont: ; preds = %entry, %lpad
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; CHECK: retl
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+define i32 @lpad_phi() personality i32 (...)* @__gxx_personality_v0 {
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+entry:
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+ store i32 42, i32* @sink_across
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+ invoke void @may_throw()
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+ to label %try.cont unwind label %lpad
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+
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+lpad: ; preds = %entry
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+ %p = phi i32 [ 11, %entry ] ; Trivial, but -O0 keeps it
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+ %0 = landingpad { i8*, i32 }
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+ catch i8* null
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+ store i32 %p, i32* @sink_across
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+ br label %try.cont
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+
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+try.cont: ; preds = %entry, %lpad
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+ %r.0 = phi i32 [ 13, %entry ], [ 55, %lpad ]
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+ ret i32 %r.0
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+}
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+
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+; The constant materialization should be *after* the stores to sink_across, but
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+; before any EH_LABEL.
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+
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+; CHECK-LABEL: lpad_phi:
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+; CHECK: movl $42, sink_across
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+; CHECK: movl $13, %{{[a-z]*}}
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+; CHECK: .Ltmp{{.*}}:
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+; CHECK: calll may_throw
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+; CHECK: .Ltmp{{.*}}:
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+; CHECK: jmp .LBB{{.*}}
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+; CHECK: .LBB{{.*}}: # %lpad
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+; CHECK-NEXT: .Ltmp{{.*}}:
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+; CHECK: movl {{.*}}, sink_across
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+; CHECK: movl $55, %{{[a-z]*}}
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+; CHECK: .LBB{{.*}}: # %try.cont
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+; CHECK: retl
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+
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+
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; Function Attrs: nounwind readnone speculatable
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declare void @llvm.dbg.value(metadata, metadata, metadata) #0
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