From 03eb38848c9f880f8d97508b6a008f81cc4bdcb9 Mon Sep 17 00:00:00 2001
From: Evan Cheng <evan.cheng@apple.com>
Date: Wed, 16 Apr 2008 23:44:44 +0000
Subject: [PATCH] Don't forget about sub-register indices when rematting
 instructions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49830 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/X86/X86InstrInfo.cpp         | 13 +++++++
 test/CodeGen/X86/2008-04-16-ReMatBug.ll | 46 +++++++++++++++++++++++++
 2 files changed, 59 insertions(+)
 create mode 100644 test/CodeGen/X86/2008-04-16-ReMatBug.ll

diff --git a/lib/Target/X86/X86InstrInfo.cpp b/lib/Target/X86/X86InstrInfo.cpp
index dcba66fcd0d..280809dc471 100644
--- a/lib/Target/X86/X86InstrInfo.cpp
+++ b/lib/Target/X86/X86InstrInfo.cpp
@@ -831,6 +831,14 @@ void X86InstrInfo::reMaterialize(MachineBasicBlock &MBB,
                                  MachineBasicBlock::iterator I,
                                  unsigned DestReg,
                                  const MachineInstr *Orig) const {
+  unsigned SubIdx = Orig->getOperand(0).isReg()
+    ? Orig->getOperand(0).getSubReg() : 0;
+  bool ChangeSubIdx = SubIdx != 0;
+  if (SubIdx && TargetRegisterInfo::isPhysicalRegister(DestReg)) {
+    DestReg = RI.getSubReg(DestReg, SubIdx);
+    SubIdx = 0;
+  }
+
   // MOV32r0 etc. are implemented with xor which clobbers condition code.
   // Re-materialize them as movri instructions to avoid side effects.
   switch (Orig->getOpcode()) {
@@ -853,6 +861,11 @@ void X86InstrInfo::reMaterialize(MachineBasicBlock &MBB,
     break;
   }
   }
+
+  if (ChangeSubIdx) {
+    MachineInstr *NewMI = prior(I);
+    NewMI->getOperand(0).setSubReg(SubIdx);
+  }
 }
 
 /// isInvariantLoad - Return true if the specified instruction (which is marked
diff --git a/test/CodeGen/X86/2008-04-16-ReMatBug.ll b/test/CodeGen/X86/2008-04-16-ReMatBug.ll
new file mode 100644
index 00000000000..3e0662aed88
--- /dev/null
+++ b/test/CodeGen/X86/2008-04-16-ReMatBug.ll
@@ -0,0 +1,46 @@
+; RUN: llvm-as < %s | llc -mtriple=i386-apple-darwin | grep movw | not grep {, %e}
+
+	%struct.DBC_t = type { i32, i8*, i16, %struct.DBC_t*, i8*, i8*, i8*, i8*, i8*, %struct.DBC_t*, i32, i32, i32, i32, i8*, i8*, i8*, i8*, i8*, i32, i32, i32, i32, i32, i32, i32, i32, i16, i16, i32*, i8, i16, %struct.DRVOPT*, i16 }
+	%struct.DRVOPT = type { i16, i32, i8, %struct.DRVOPT* }
+	%struct.GENV_t = type { i32, i8*, i16, i8*, i8*, i32, i32, i32, i32, %struct.DBC_t*, i16 }
+	%struct.pthread_mutex_t = type { i32, [40 x i8] }
+@iodbcdm_global_lock = external global %struct.pthread_mutex_t		; <%struct.pthread_mutex_t*> [#uses=1]
+
+define i16 @SQLDriversW(i8* %henv, i16 zeroext  %fDir, i32* %szDrvDesc, i16 signext  %cbDrvDescMax, i16* %pcbDrvDesc, i32* %szDrvAttr, i16 signext  %cbDrvAttrMax, i16* %pcbDrvAttr) signext nounwind  {
+entry:
+	%tmp12 = bitcast i8* %henv to %struct.GENV_t*		; <%struct.GENV_t*> [#uses=1]
+	br i1 true, label %bb28, label %bb
+bb:		; preds = %entry
+	ret i16 0
+bb28:		; preds = %entry
+	br i1 false, label %bb37, label %done
+bb37:		; preds = %bb28
+	%tmp46 = getelementptr %struct.GENV_t* %tmp12, i32 0, i32 10		; <i16*> [#uses=1]
+	store i16 0, i16* %tmp46, align 4
+	br i1 false, label %bb74, label %bb92
+bb74:		; preds = %bb37
+	br label %bb92
+bb92:		; preds = %bb74, %bb37
+	%tmp95180 = shl i16 %cbDrvAttrMax, 2		; <i16> [#uses=1]
+	%tmp100178 = shl i16 %cbDrvDescMax, 2		; <i16> [#uses=1]
+	%tmp113 = tail call i16 @SQLDrivers_Internal( i8* %henv, i16 zeroext  %fDir, i8* null, i16 signext  %tmp100178, i16* %pcbDrvDesc, i8* null, i16 signext  %tmp95180, i16* %pcbDrvAttr, i8 zeroext  87 ) signext nounwind 		; <i16> [#uses=1]
+	br i1 false, label %done, label %bb137
+bb137:		; preds = %bb92
+	ret i16 0
+done:		; preds = %bb92, %bb28
+	%retcode.0 = phi i16 [ -2, %bb28 ], [ %tmp113, %bb92 ]		; <i16> [#uses=2]
+	br i1 false, label %bb167, label %bb150
+bb150:		; preds = %done
+	%tmp157158 = sext i16 %retcode.0 to i32		; <i32> [#uses=1]
+	tail call void @trace_SQLDriversW( i32 1, i32 %tmp157158, i8* %henv, i16 zeroext  %fDir, i32* %szDrvDesc, i16 signext  %cbDrvDescMax, i16* %pcbDrvDesc, i32* %szDrvAttr, i16 signext  %cbDrvAttrMax, i16* %pcbDrvAttr ) nounwind 
+	ret i16 0
+bb167:		; preds = %done
+	%tmp168 = tail call i32 @pthread_mutex_unlock( %struct.pthread_mutex_t* @iodbcdm_global_lock ) nounwind 		; <i32> [#uses=0]
+	ret i16 %retcode.0
+}
+
+declare i32 @pthread_mutex_unlock(%struct.pthread_mutex_t*)
+
+declare i16 @SQLDrivers_Internal(i8*, i16 zeroext , i8*, i16 signext , i16*, i8*, i16 signext , i16*, i8 zeroext ) signext nounwind 
+
+declare void @trace_SQLDriversW(i32, i32, i8*, i16 zeroext , i32*, i16 signext , i16*, i32*, i16 signext , i16*)