Add a new MOV8rr_NOREX, and make X86's copyRegToReg use it when
either the source or destination is a physical h register.
This fixes sqlite3 with the post-RA scheduler enabled.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@69111 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86InstrInfo.cpp b/lib/Target/X86/X86InstrInfo.cpp
index 77955a6..e64b296 100644
--- a/lib/Target/X86/X86InstrInfo.cpp
+++ b/lib/Target/X86/X86InstrInfo.cpp
@@ -1641,6 +1641,11 @@
return Count;
}
+/// isHReg - Test if the given register is a physical h register.
+static bool isHReg(unsigned Reg) {
+ return Reg == X86::AH || Reg == X86::BH || Reg == X86::CH || Reg == X86::DH;
+}
+
bool X86InstrInfo::copyRegToReg(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI,
unsigned DestReg, unsigned SrcReg,
@@ -1658,7 +1663,12 @@
} else if (DestRC == &X86::GR16RegClass) {
Opc = X86::MOV16rr;
} else if (DestRC == &X86::GR8RegClass) {
- Opc = X86::MOV8rr;
+ // Copying two or from a physical H register requires a NOREX move. Otherwise
+ // use a normal move.
+ if (isHReg(DestReg) || isHReg(SrcReg))
+ Opc = X86::MOV8rr_NOREX;
+ else
+ Opc = X86::MOV8rr;
} else if (DestRC == &X86::GR64_RegClass) {
Opc = X86::MOV64rr;
} else if (DestRC == &X86::GR32_RegClass) {
diff --git a/lib/Target/X86/X86InstrInfo.td b/lib/Target/X86/X86InstrInfo.td
index 077b456..4fd3320 100644
--- a/lib/Target/X86/X86InstrInfo.td
+++ b/lib/Target/X86/X86InstrInfo.td
@@ -783,10 +783,15 @@
"mov{l}\t{$src, $dst|$dst, $src}",
[(store GR32:$src, addr:$dst)]>;
-// A version of MOV8mr that uses i8mem_NOREX so that it can be used for
-// storing h registers, which can't be encoded when a REX prefix is present.
-def MOV8mr_NOREX : I<0x88, MRMDestMem, (outs), (ins i8mem_NOREX:$dst, GR8:$src),
- "mov{b}\t{$src, $dst|$dst, $src} # NOREX", []>;
+// Versions of MOV8rr and MOV8mr that use i8mem_NOREX and GR8_NOREX so that they
+// can be used for copying and storing h registers, which can't be encoded when
+// a REX prefix is present.
+let neverHasSideEffects = 1 in
+def MOV8rr_NOREX : I<0x88, MRMDestReg, (outs GR8_NOREX:$dst), (ins GR8_NOREX:$src),
+ "mov{b}\t{$src, $dst|$dst, $src} # NOREX", []>;
+def MOV8mr_NOREX : I<0x88, MRMDestMem,
+ (outs), (ins i8mem_NOREX:$dst, GR8_NOREX:$src),
+ "mov{b}\t{$src, $dst|$dst, $src} # NOREX", []>;
//===----------------------------------------------------------------------===//
// Fixed-Register Multiplication and Division Instructions...