Do not use the inefficient, fixed function, CBW, CDQ, ... instructions

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@6844 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/X86/InstSelectSimple.cpp b/lib/Target/X86/InstSelectSimple.cpp
index a7c3c648c8b1a57217fc9051688e68e081e649f5..0566defd0523a137719be8aad1164ba45b24802a 100644 (file)
--- a/lib/Target/X86/InstSelectSimple.cpp
+++ b/lib/Target/X86/InstSelectSimple.cpp
@@ -1179,7 +1179,7 @@ void ISel::visitDivRem(BinaryOperator &I) {
 
   static const unsigned Regs[]     ={ X86::AL    , X86::AX     , X86::EAX     };
   static const unsigned MovOpcode[]={ X86::MOVrr8, X86::MOVrr16, X86::MOVrr32 };
-  static const unsigned ExtOpcode[]={ X86::CBW   , X86::CWD    , X86::CDQ     };
+  static const unsigned SarOpcode[]={ X86::SARir8, X86::SARir16, X86::SARir32 };
   static const unsigned ClrOpcode[]={ X86::XORrr8, X86::XORrr16, X86::XORrr32 };
   static const unsigned ExtRegs[]  ={ X86::AH    , X86::DX     , X86::EDX     };
 
@@ -1197,7 +1197,9 @@ void ISel::visitDivRem(BinaryOperator &I) {
 
   if (isSigned) {
     // Emit a sign extension instruction...
-    BuildMI(BB, ExtOpcode[Class], 0);
+    unsigned ShiftResult = makeAnotherReg(I.getType());
+    BuildMI(BB, SarOpcode[Class], 2, ShiftResult).addReg(Op0Reg).addZImm(31);
+    BuildMI(BB, MovOpcode[Class], 1, ExtReg).addReg(ShiftResult);
   } else {
     // If unsigned, emit a zeroing instruction... (reg = xor reg, reg)
     BuildMI(BB, ClrOpcode[Class], 2, ExtReg).addReg(ExtReg).addReg(ExtReg);

diff --git a/lib/Target/X86/X86ISelSimple.cpp b/lib/Target/X86/X86ISelSimple.cpp
index a7c3c648c8b1a57217fc9051688e68e081e649f5..0566defd0523a137719be8aad1164ba45b24802a 100644 (file)
--- a/lib/Target/X86/X86ISelSimple.cpp
+++ b/lib/Target/X86/X86ISelSimple.cpp
@@ -1179,7 +1179,7 @@ void ISel::visitDivRem(BinaryOperator &I) {
 
   static const unsigned Regs[]     ={ X86::AL    , X86::AX     , X86::EAX     };
   static const unsigned MovOpcode[]={ X86::MOVrr8, X86::MOVrr16, X86::MOVrr32 };
-  static const unsigned ExtOpcode[]={ X86::CBW   , X86::CWD    , X86::CDQ     };
+  static const unsigned SarOpcode[]={ X86::SARir8, X86::SARir16, X86::SARir32 };
   static const unsigned ClrOpcode[]={ X86::XORrr8, X86::XORrr16, X86::XORrr32 };
   static const unsigned ExtRegs[]  ={ X86::AH    , X86::DX     , X86::EDX     };
 
@@ -1197,7 +1197,9 @@ void ISel::visitDivRem(BinaryOperator &I) {
 
   if (isSigned) {
     // Emit a sign extension instruction...
-    BuildMI(BB, ExtOpcode[Class], 0);
+    unsigned ShiftResult = makeAnotherReg(I.getType());
+    BuildMI(BB, SarOpcode[Class], 2, ShiftResult).addReg(Op0Reg).addZImm(31);
+    BuildMI(BB, MovOpcode[Class], 1, ExtReg).addReg(ShiftResult);
   } else {
     // If unsigned, emit a zeroing instruction... (reg = xor reg, reg)
     BuildMI(BB, ClrOpcode[Class], 2, ExtReg).addReg(ExtReg).addReg(ExtReg);