[llvm-commits] [llvm] r137993 - in /llvm/trunk: include/llvm/CodeGen/FastISel.h lib/CodeGen/SelectionDAG/FastISel.cpp test/CodeGen/ARM/debug-info-blocks.ll test/CodeGen/X86/fast-isel-x86-64.ll
Ivan Krasin
krasin at chromium.org
Thu Aug 18 15:06:11 PDT 2011
Author: krasin
Date: Thu Aug 18 17:06:10 2011
New Revision: 137993
URL: http://llvm.org/viewvc/llvm-project?rev=137993&view=rev
Log:
FastISel: avoid function calls between the materialization of the constant and its use.
Modified:
llvm/trunk/include/llvm/CodeGen/FastISel.h
llvm/trunk/lib/CodeGen/SelectionDAG/FastISel.cpp
llvm/trunk/test/CodeGen/ARM/debug-info-blocks.ll
llvm/trunk/test/CodeGen/X86/fast-isel-x86-64.ll
Modified: llvm/trunk/include/llvm/CodeGen/FastISel.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/FastISel.h?rev=137993&r1=137992&r2=137993&view=diff
==============================================================================
--- llvm/trunk/include/llvm/CodeGen/FastISel.h (original)
+++ llvm/trunk/include/llvm/CodeGen/FastISel.h Thu Aug 18 17:06:10 2011
@@ -54,8 +54,18 @@
const TargetInstrInfo &TII;
const TargetLowering &TLI;
const TargetRegisterInfo &TRI;
+
+ /// The position of the last instruction for materializing constants
+ /// for use in the current block. It resets to EmitStartPt when it
+ /// makes sense (for example, it's usually profitable to avoid function
+ /// calls between the definition and the use)
MachineInstr *LastLocalValue;
+ /// The top most instruction in the current block that is allowed for
+ /// emitting local variables. LastLocalValue resets to EmitStartPt when
+ /// it makes sense (for example, on function calls)
+ MachineInstr *EmitStartPt;
+
public:
/// getLastLocalValue - Return the position of the last instruction
/// emitted for materializing constants for use in the current block.
@@ -63,7 +73,10 @@
/// setLastLocalValue - Update the position of the last instruction
/// emitted for materializing constants for use in the current block.
- void setLastLocalValue(MachineInstr *I) { LastLocalValue = I; }
+ void setLastLocalValue(MachineInstr *I) {
+ EmitStartPt = I;
+ LastLocalValue = I;
+ }
/// startNewBlock - Set the current block to which generated machine
/// instructions will be appended, and clear the local CSE map.
@@ -358,6 +371,11 @@
/// be materialized with new instructions.
unsigned materializeRegForValue(const Value *V, MVT VT);
+ /// flushLocalValueMap - clears LocalValueMap and moves the area for the
+ /// new local variables to the beginning of the block. It helps to avoid
+ /// spilling cached variables across heavy instructions like calls.
+ void flushLocalValueMap();
+
/// hasTrivialKill - Test whether the given value has exactly one use.
bool hasTrivialKill(const Value *V) const;
};
Modified: llvm/trunk/lib/CodeGen/SelectionDAG/FastISel.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/FastISel.cpp?rev=137993&r1=137992&r2=137993&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/FastISel.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/FastISel.cpp Thu Aug 18 17:06:10 2011
@@ -66,17 +66,22 @@
void FastISel::startNewBlock() {
LocalValueMap.clear();
- // Start out as null, meaining no local-value instructions have
- // been emitted.
- LastLocalValue = 0;
+ EmitStartPt = 0;
- // Advance the last local value past any EH_LABEL instructions.
+ // Advance the emit start point past any EH_LABEL instructions.
MachineBasicBlock::iterator
I = FuncInfo.MBB->begin(), E = FuncInfo.MBB->end();
while (I != E && I->getOpcode() == TargetOpcode::EH_LABEL) {
- LastLocalValue = I;
+ EmitStartPt = I;
++I;
}
+ LastLocalValue = EmitStartPt;
+}
+
+void FastISel::flushLocalValueMap() {
+ LocalValueMap.clear();
+ LastLocalValue = EmitStartPt;
+ recomputeInsertPt();
}
bool FastISel::hasTrivialKill(const Value *V) const {
@@ -645,6 +650,16 @@
}
}
+ // Usually, it does not make sense to initialize a value,
+ // make an unrelated function call and use the value, because
+ // it tends to be spilled on the stack. So, we move the pointer
+ // to the last local value to the beginning of the block, so that
+ // all the values which have already been materialized,
+ // appear after the call. It also makes sense to skip intrinsics
+ // since they tend to be inlined.
+ if (!isa<IntrinsicInst>(F))
+ flushLocalValueMap();
+
// An arbitrary call. Bail.
return false;
}
Modified: llvm/trunk/test/CodeGen/ARM/debug-info-blocks.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/ARM/debug-info-blocks.ll?rev=137993&r1=137992&r2=137993&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/ARM/debug-info-blocks.ll (original)
+++ llvm/trunk/test/CodeGen/ARM/debug-info-blocks.ll Thu Aug 18 17:06:10 2011
@@ -1,5 +1,5 @@
; RUN: llc -O0 < %s | FileCheck %s
-; CHECK: @DEBUG_VALUE: mydata <- [sp+#8]+#0
+; CHECK: @DEBUG_VALUE: mydata <- [sp+#4]+#0
; Radar 9331779
target datalayout = "e-p:32:32:32-i1:8:32-i8:8:32-i16:16:32-i32:32:32-i64:32:32-f32:32:32-f64:32:32-v64:32:64-v128:32:128-a0:0:32-n32"
target triple = "thumbv7-apple-macosx10.7.0"
Modified: llvm/trunk/test/CodeGen/X86/fast-isel-x86-64.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/fast-isel-x86-64.ll?rev=137993&r1=137992&r2=137993&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/fast-isel-x86-64.ll (original)
+++ llvm/trunk/test/CodeGen/X86/fast-isel-x86-64.ll Thu Aug 18 17:06:10 2011
@@ -259,4 +259,27 @@
; CHECK: test21:
; CHECK-NOT: pxor
; CHECK: movsd LCPI
-}
\ No newline at end of file
+}
+
+; Check that immediate arguments to a function
+; do not cause massive spilling and are used
+; as immediates just before the call.
+define void @test22() nounwind {
+entry:
+ call void @foo22(i32 0)
+ call void @foo22(i32 1)
+ call void @foo22(i32 2)
+ call void @foo22(i32 3)
+ ret void
+; CHECK: test22:
+; CHECK: movl $0, %edi
+; CHECK: callq _foo22
+; CHECK: movl $1, %edi
+; CHECK: callq _foo22
+; CHECK: movl $2, %edi
+; CHECK: callq _foo22
+; CHECK: movl $3, %edi
+; CHECK: callq _foo22
+}
+
+declare void @foo22(i32)
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