diff options
| -rw-r--r-- | lib/Target/X86/X86VZeroUpper.cpp | 35 | ||||
| -rw-r--r-- | test/CodeGen/X86/pr17631.ll | 20 |
2 files changed, 43 insertions, 12 deletions
diff --git a/lib/Target/X86/X86VZeroUpper.cpp b/lib/Target/X86/X86VZeroUpper.cpp index 0d37a7d..a944652 100644 --- a/lib/Target/X86/X86VZeroUpper.cpp +++ b/lib/Target/X86/X86VZeroUpper.cpp @@ -148,6 +148,25 @@ static bool hasYmmReg(MachineInstr *MI) { return false; } +/// clobbersAnyYmmReg() - Check if any YMM register will be clobbered by this +/// instruction. +static bool clobbersAnyYmmReg(MachineInstr *MI) { + for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) { + const MachineOperand &MO = MI->getOperand(i); + if (!MO.isRegMask()) + continue; + for (unsigned reg = X86::YMM0; reg < X86::YMM31; ++reg) { + if (MO.clobbersPhysReg(reg)) + return true; + } + for (unsigned reg = X86::ZMM0; reg < X86::ZMM31; ++reg) { + if (MO.clobbersPhysReg(reg)) + return true; + } + } + return false; +} + /// runOnMachineFunction - Loop over all of the basic blocks, inserting /// vzero upper instructions before function calls. bool VZeroUpperInserter::runOnMachineFunction(MachineFunction &MF) { @@ -234,14 +253,6 @@ bool VZeroUpperInserter::processBasicBlock(MachineFunction &MF, DebugLoc dl = I->getDebugLoc(); MachineInstr *MI = I; - // Don't need to check instructions added in prolog. - // In prolog, special function calls may be added for specific targets - // (e.g. on Windows, a prolog helper '_chkstk' is called when the local - // variables exceed 4K bytes on stack.) These helpers won't use/def YMM/XMM - // registers. - if (MI->getFlag(MachineInstr::FrameSetup)) - continue; - bool isControlFlow = MI->isCall() || MI->isReturn(); // Shortcut: don't need to check regular instructions in dirty state. @@ -260,6 +271,14 @@ bool VZeroUpperInserter::processBasicBlock(MachineFunction &MF, if (!isControlFlow) continue; + // If the call won't clobber any YMM register, skip it as well. It usually + // happens on helper function calls (such as '_chkstk', '_ftol2') where + // standard calling convention is not used (RegMask is not used to mark + // register clobbered and register usage (def/imp-def/use) is well-dfined + // and explicitly specified. + if (MI->isCall() && !clobbersAnyYmmReg(MI)) + continue; + BBHasCall = true; // The VZEROUPPER instruction resets the upper 128 bits of all Intel AVX diff --git a/test/CodeGen/X86/pr17631.ll b/test/CodeGen/X86/pr17631.ll index a572ff2..98f951f 100644 --- a/test/CodeGen/X86/pr17631.ll +++ b/test/CodeGen/X86/pr17631.ll @@ -1,16 +1,16 @@ ; RUN: llc < %s -mcpu=core-avx-i -mtriple=i386-pc-win32 | FileCheck %s - + %struct_type = type { [64 x <8 x float>], <8 x float> } - + ; Function Attrs: nounwind readnone declare i32 @llvm.x86.avx.movmsk.ps.256(<8 x float>) - + ; Function Attrs: nounwind define i32 @equal(<8 x i32> %A) { allocas: %first_alloc = alloca [64 x <8 x i32>] %second_alloc = alloca %struct_type - + %A1 = bitcast <8 x i32> %A to <8 x float> %A2 = call i32 @llvm.x86.avx.movmsk.ps.256(<8 x float> %A1) ret i32 %A2 @@ -20,3 +20,15 @@ allocas: ; CHECK-NOT: vzeroupper ; CHECK: _chkstk ; CHECK: ret + +define <8 x float> @foo(<8 x float> %y, i64* %p, double %x) { + %i = fptoui double %x to i64 + store i64 %i, i64* %p + %ret = fadd <8 x float> %y, %y + ret <8 x float> %ret +} + +; CHECK: foo +; CHECK-NOT: vzeroupper +; CHECK: _ftol2 +; CHECK: ret |