116 lines
3.7 KiB
Diff
116 lines
3.7 KiB
Diff
From b9b016cda57d8afc26a150de7ee329b54a994c85 Mon Sep 17 00:00:00 2001
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From: Michael Liao <michael.hliao@gmail.com>
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Date: Mon, 21 Oct 2013 17:47:58 -0700
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Subject: [PATCH] Fix PR17631
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- Skip instructions added in prolog. For specific targets, prolog may
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insert helper function calls (e.g. _chkstk will be called when
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there're more than 4K bytes allocated on stack). However, these
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helpers don't use/def YMM/XMM registers.
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It also include second fix for the problem: r196261+r196391.
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diff --git a/lib/Target/X86/X86VZeroUpper.cpp b/lib/Target/X86/X86VZeroUpper.cpp
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index 477f75a..0d37a7d 100644
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--- lib/Target/X86/X86VZeroUpper.cpp
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+++ lib/Target/X86/X86VZeroUpper.cpp
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@@ -121,7 +121,7 @@
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}
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static bool clobbersAllYmmRegs(const MachineOperand &MO) {
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- for (unsigned reg = X86::YMM0; reg < X86::YMM15; ++reg) {
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+ for (unsigned reg = X86::YMM0; reg <= X86::YMM15; ++reg) {
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if (!MO.clobbersPhysReg(reg))
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return false;
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}
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@@ -143,6 +143,21 @@
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return false;
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}
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+/// clobbersAnyYmmReg() - Check if any YMM register will be clobbered by this
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+/// instruction.
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+static bool clobbersAnyYmmReg(MachineInstr *MI) {
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+ for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
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+ const MachineOperand &MO = MI->getOperand(i);
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+ if (!MO.isRegMask())
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+ continue;
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+ for (unsigned reg = X86::YMM0; reg <= X86::YMM15; ++reg) {
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+ if (MO.clobbersPhysReg(reg))
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+ return true;
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+ }
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+ }
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+ return false;
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+}
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+
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/// runOnMachineFunction - Loop over all of the basic blocks, inserting
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/// vzero upper instructions before function calls.
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bool VZeroUpperInserter::runOnMachineFunction(MachineFunction &MF) {
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@@ -226,8 +241,9 @@
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bool BBHasCall = false;
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for (MachineBasicBlock::iterator I = BB.begin(); I != BB.end(); ++I) {
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+ DebugLoc dl = I->getDebugLoc();
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MachineInstr *MI = I;
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- DebugLoc dl = I->getDebugLoc();
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+
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bool isControlFlow = MI->isCall() || MI->isReturn();
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// Shortcut: don't need to check regular instructions in dirty state.
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@@ -246,6 +262,14 @@
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if (!isControlFlow)
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continue;
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+ // If the call won't clobber any YMM register, skip it as well. It usually
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+ // happens on helper function calls (such as '_chkstk', '_ftol2') where
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+ // standard calling convention is not used (RegMask is not used to mark
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+ // register clobbered and register usage (def/imp-def/use) is well-dfined
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+ // and explicitly specified.
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+ if (MI->isCall() && !clobbersAnyYmmReg(MI))
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+ continue;
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+
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BBHasCall = true;
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// The VZEROUPPER instruction resets the upper 128 bits of all Intel AVX
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diff --git a/test/CodeGen/X86/pr17631.ll b/test/CodeGen/X86/pr17631.ll
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new file mode 100644
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index 0000000..a572ff2
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--- /dev/null
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+++ test/CodeGen/X86/pr17631.ll
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@@ -0,0 +1,34 @@
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+; RUN: llc < %s -mcpu=core-avx-i -mtriple=i386-pc-win32 | FileCheck %s
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+
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+%struct_type = type { [64 x <8 x float>], <8 x float> }
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+
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+; Function Attrs: nounwind readnone
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+declare i32 @llvm.x86.avx.movmsk.ps.256(<8 x float>)
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+
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+; Function Attrs: nounwind
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+define i32 @equal(<8 x i32> %A) {
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+allocas:
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+ %first_alloc = alloca [64 x <8 x i32>]
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+ %second_alloc = alloca %struct_type
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+
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+ %A1 = bitcast <8 x i32> %A to <8 x float>
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+ %A2 = call i32 @llvm.x86.avx.movmsk.ps.256(<8 x float> %A1)
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+ ret i32 %A2
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+}
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+
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+; CHECK: equal
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+; CHECK-NOT: vzeroupper
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+; CHECK: _chkstk
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+; CHECK: ret
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+
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+define <8 x float> @foo(<8 x float> %y, i64* %p, double %x) {
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+ %i = fptoui double %x to i64
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+ store i64 %i, i64* %p
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+ %ret = fadd <8 x float> %y, %y
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+ ret <8 x float> %ret
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+}
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+
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+; CHECK: foo
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+; CHECK-NOT: vzeroupper
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+; CHECK: _ftol2
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+; CHECK: ret
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--
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1.8.1.2
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