[llvm] 8d7ccb3 - Set the floating point status register as reserved

[Pengfei Wang via llvm-commits]

Author: Pengfei Wang
Date: 2019-11-03T23:14:34-08:00
New Revision: 8d7ccb37440e11552cb4a0bb989ddee5031700a4

URL: https://github.com/llvm/llvm-project/commit/8d7ccb37440e11552cb4a0bb989ddee5031700a4
DIFF: https://github.com/llvm/llvm-project/commit/8d7ccb37440e11552cb4a0bb989ddee5031700a4.diff

LOG:  Set the floating point status register as reserved

Summary:
This patch sets the FPSW (X87 floating-point status register) as a reserved
physical register and fix the test failure caused by [[ https://reviews.llvm.org/D68854| D68854 ]].

Before this patch, some tests will fail because it implicit uses FPSW without
define it. Setting the FPSW as a reserved physical register will skip liveness
analysis because it is always live.

Reviewers: pengfei, craig.topper

Reviewed By: craig.topper

Subscribers: craig.topper, hiraditya, llvm-commits

Patch by LiuChen.

Differential Revision: https://reviews.llvm.org/D69784

Added: 
    

Modified: 
    llvm/lib/Target/X86/X86RegisterInfo.cpp
    llvm/test/CodeGen/X86/pr34080-2.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/X86/X86RegisterInfo.cpp b/llvm/lib/Target/X86/X86RegisterInfo.cpp
index 024a13fa931e..3809a14178fd 100644
--- a/llvm/lib/Target/X86/X86RegisterInfo.cpp
+++ b/llvm/lib/Target/X86/X86RegisterInfo.cpp
@@ -523,6 +523,9 @@ BitVector X86RegisterInfo::getReservedRegs(const MachineFunction &MF) const {
   // Set the floating point control register as reserved.
   Reserved.set(X86::FPCW);
 
+  // Set the floating point status register as reserved.
+  Reserved.set(X86::FPSW);
+
   // Set the SIMD floating point control register as reserved.
   Reserved.set(X86::MXCSR);
 

diff  --git a/llvm/test/CodeGen/X86/pr34080-2.ll b/llvm/test/CodeGen/X86/pr34080-2.ll
index cb3e22d5e1bf..f56c01fbcbb0 100644
--- a/llvm/test/CodeGen/X86/pr34080-2.ll
+++ b/llvm/test/CodeGen/X86/pr34080-2.ll
@@ -62,13 +62,13 @@ define void @computeJD(%struct.DateTime*) nounwind {
 ; CHECK-NEXT:    imull $60000, 24(%ebx), %ecx # imm = 0xEA60
 ; CHECK-NEXT:    addl %eax, %ecx
 ; CHECK-NEXT:    fldl 28(%ebx)
+; CHECK-NEXT:    fmuls {{\.LCPI.*}}
 ; CHECK-NEXT:    fnstcw {{[0-9]+}}(%esp)
 ; CHECK-NEXT:    movzwl {{[0-9]+}}(%esp), %eax
 ; CHECK-NEXT:    orl $3072, %eax # imm = 0xC00
 ; CHECK-NEXT:    movw %ax, {{[0-9]+}}(%esp)
 ; CHECK-NEXT:    movl %ecx, %eax
 ; CHECK-NEXT:    sarl $31, %eax
-; CHECK-NEXT:    fmuls {{\.LCPI.*}}
 ; CHECK-NEXT:    fldcw {{[0-9]+}}(%esp)
 ; CHECK-NEXT:    fistpll {{[0-9]+}}(%esp)
 ; CHECK-NEXT:    fldcw {{[0-9]+}}(%esp)