From: Michael Kuperstein <michael.m.kuperstein@intel.com>
Date: Wed, 16 Sep 2015 11:27:20 +0000 (+0000)
Subject: [X86] Do not generate 64-bit pops of 32-bit GPRs.
X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=196a1036c4a0487225e4ee9dd7ce71654a8159eb;p=oota-llvm.git

[X86] Do not generate 64-bit pops of 32-bit GPRs.

When trying emit a stack adjustments using pops, frame lowering selects an
arbitrary free GPR. It should always select one from an appropriate class...
This fixes PR24649.

Patch by: amjad.aboud@intel.com
Differential Revision: http://reviews.llvm.org/D12609


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247785 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Target/X86/X86FrameLowering.cpp b/lib/Target/X86/X86FrameLowering.cpp
index edc41145a7d..c9715f1ae84 100644
--- a/lib/Target/X86/X86FrameLowering.cpp
+++ b/lib/Target/X86/X86FrameLowering.cpp
@@ -1935,6 +1935,9 @@ void X86FrameLowering::adjustForHiPEPrologue(
 bool X86FrameLowering::adjustStackWithPops(MachineBasicBlock &MBB,
     MachineBasicBlock::iterator MBBI, DebugLoc DL, int Offset) const {
 
+  if (Offset <= 0)
+    return false;
+
   if (Offset % SlotSize)
     return false;
 
@@ -1955,9 +1958,11 @@ bool X86FrameLowering::adjustStackWithPops(MachineBasicBlock &MBB,
   unsigned FoundRegs = 0;
 
   auto RegMask = Prev->getOperand(1);
-  
-  // Try to find up to NumPops free registers. 
-  for (auto Candidate : X86::GR32_NOREX_NOSPRegClass) {
+
+  auto &RegClass =
+      Is64Bit ? X86::GR64_NOREX_NOSPRegClass : X86::GR32_NOREX_NOSPRegClass;
+  // Try to find up to NumPops free registers.
+  for (auto Candidate : RegClass) {
 
     // Poor man's liveness:
     // Since we're immediately after a call, any register that is clobbered
diff --git a/test/CodeGen/X86/pop-stack-cleanup.ll b/test/CodeGen/X86/pop-stack-cleanup.ll
index c6fb2d8885b..3a22cc19100 100644
--- a/test/CodeGen/X86/pop-stack-cleanup.ll
+++ b/test/CodeGen/X86/pop-stack-cleanup.ll
@@ -1,10 +1,13 @@
-; RUN: llc < %s -mtriple=i686-windows | FileCheck %s -check-prefix=CHECK -check-prefix=NORMAL
+; RUN: llc < %s -mtriple=i686-windows | FileCheck %s -check-prefix=CHECK 
+; RUN: llc < %s -mtriple=x86_64-linux | FileCheck %s -check-prefix=LINUX64
 
 declare void @param1(i32 %a)
 declare i32 @param2_ret(i32 %a, i32 %b)
 declare i64 @param2_ret64(i32 %a, i32 %b)
 declare void @param2(i32 %a, i32 %b)
 declare void @param3(i32 %a, i32 %b, i32 %c)
+declare void @param8(i64, i64, i64, i64, i64, i64, i64, i64)
+
 
 define void @test() minsize {
 ; CHECK-LABEL: test:
@@ -59,3 +62,15 @@ define void @spill(i32 inreg %a, i32 inreg %b, i32 inreg %c) minsize {
   call void @spill(i32 %a, i32 %b, i32 %c)
   ret void
 }
+
+define void @test_linux64(i32 %size) minsize {
+; LINUX64-LABEL: test_linux64:
+; LINUX64: pushq %rbp
+; LINUX64: callq param8
+; LINUX64-NEXT: popq %rax
+; LINUX64-NEXT: popq %rcx
+
+  %a = alloca i64, i32 %size, align 8
+  call void @param8(i64 1, i64 2, i64 3, i64 4, i64 5, i64 6, i64 7, i64 8)
+  ret void
+}