Be more careful with insert_subreg and extract_subreg where either source or destination operand has already been coalesced with another register that's defined by a insert_subreg or extract_subreg.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49843 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 225 insertions, 27 deletions

diff --git a/lib/CodeGen/SimpleRegisterCoalescing.cpp b/lib/CodeGen/SimpleRegisterCoalescing.cpp
index 3c69b25..c9b5fd6 100644
--- a/lib/CodeGen/SimpleRegisterCoalescing.cpp
+++ b/lib/CodeGen/SimpleRegisterCoalescing.cpp
@@ -849,20 +849,28 @@ bool SimpleRegisterCoalescing::JoinCopy(CopyRec &TheCopy, bool &Again) {
       // r1024 = EXTRACT_SUBREG EAX, 0 then r1024 is really going to be
       // coalesced with AX.
       unsigned DstSubIdx = CopyMI->getOperand(0).getSubReg();
-      assert(!DstSubIdx || DstSubIdx == SubIdx);
-      if (DstSubIdx != SubIdx)
-        // r1024<2> = EXTRACT_SUBREG EAX, 0. Then r1024 has already been
-        // coalesced to an INSERT_SUBREG so the subreg indices cancel out.
+      if (DstSubIdx) {
+        // r1024<2> = EXTRACT_SUBREG EAX, 2. Then r1024 has already been
+        // coalesced to a larger register so the subreg indices cancel out.
+        if (DstSubIdx != SubIdx) {
+          DOUT << "\t Sub-register indices mismatch.\n";
+          return false; // Not coalescable.
+        }
+      } else
         SrcReg = tri_->getSubReg(SrcReg, SubIdx);
       SubIdx = 0;
     } else if (DstIsPhys && isInsSubReg) {
       // EAX = INSERT_SUBREG EAX, r1024, 0
       unsigned SrcSubIdx = CopyMI->getOperand(2).getSubReg();
-      assert(!SrcSubIdx || SrcSubIdx == SubIdx);
-      if (SrcSubIdx != SubIdx)
-        // EAX = INSERT_SUBREG EAX, r1024<2>, 0 Then r1024 has already been
-        // coalesced to an EXTRACT_SUBREG so the subreg indices cancel out.
-      DstReg = tri_->getSubReg(DstReg, SubIdx);
+      if (SrcSubIdx) {
+        // EAX = INSERT_SUBREG EAX, r1024<2>, 2 Then r1024 has already been
+        // coalesced to a larger register so the subreg indices cancel out.
+        if (SrcSubIdx != SubIdx) {
+          DOUT << "\t Sub-register indices mismatch.\n";
+          return false; // Not coalescable.
+        }
+      } else
+        DstReg = tri_->getSubReg(DstReg, SubIdx);
       SubIdx = 0;
     } else if ((DstIsPhys && isExtSubReg) || (SrcIsPhys && isInsSubReg)) {
       // If this is a extract_subreg where dst is a physical register, e.g.
@@ -870,6 +878,11 @@ bool SimpleRegisterCoalescing::JoinCopy(CopyRec &TheCopy, bool &Again) {
       // then create and update the actual physical register allocated to RHS.
       // Ditto for
       // reg1024 = INSERT_SUBREG r1024, cl, 1
+      if (CopyMI->getOperand(1).getSubReg()) {
+        DOUT << "\tSrc of extract_ / insert_subreg already coalesced with reg"
+             << " of a super-class.\n";
+        return false; // Not coalescable.
+      }
       const TargetRegisterClass *RC =
         mri_->getRegClass(isExtSubReg ? SrcReg : DstReg);
       if (isExtSubReg) {
@@ -899,24 +912,38 @@ bool SimpleRegisterCoalescing::JoinCopy(CopyRec &TheCopy, bool &Again) {
         }
       SubIdx = 0;
     } else {
-      unsigned LargeReg = isExtSubReg ? SrcReg : DstReg;
-      unsigned SmallReg = isExtSubReg ? DstReg : SrcReg;
-      unsigned LargeRegSize =
-        li_->getInterval(LargeReg).getSize() / InstrSlots::NUM;
-      unsigned SmallRegSize =
-        li_->getInterval(SmallReg).getSize() / InstrSlots::NUM;
-      const TargetRegisterClass *RC = mri_->getRegClass(SmallReg);
-      unsigned Threshold = allocatableRCRegs_[RC].count();
-      // Be conservative. If both sides are virtual registers, do not coalesce
-      // if this will cause a high use density interval to target a smaller set
-      // of registers.
-      if (SmallRegSize > Threshold || LargeRegSize > Threshold) {
-        LiveVariables::VarInfo &svi = lv_->getVarInfo(LargeReg);
-        LiveVariables::VarInfo &dvi = lv_->getVarInfo(SmallReg);
-        if ((float)dvi.NumUses / SmallRegSize <
-            (float)svi.NumUses / LargeRegSize) {
-          Again = true;  // May be possible to coalesce later.
-          return false;
+      unsigned OldSubIdx = isExtSubReg ? CopyMI->getOperand(0).getSubReg()
+        : CopyMI->getOperand(2).getSubReg();
+      if (OldSubIdx) {
+        if (OldSubIdx == SubIdx)
+          // r1024<2> = EXTRACT_SUBREG r1025, 2. Then r1024 has already been
+          // coalesced to a larger register so the subreg indices cancel out.
+          SubIdx = 0;
+        else {
+          DOUT << "\t Sub-register indices mismatch.\n";
+          return false; // Not coalescable.
+        }
+      }
+      if (SubIdx) {
+        unsigned LargeReg = isExtSubReg ? SrcReg : DstReg;
+        unsigned SmallReg = isExtSubReg ? DstReg : SrcReg;
+        unsigned LargeRegSize =
+          li_->getInterval(LargeReg).getSize() / InstrSlots::NUM;
+        unsigned SmallRegSize =
+          li_->getInterval(SmallReg).getSize() / InstrSlots::NUM;
+        const TargetRegisterClass *RC = mri_->getRegClass(SmallReg);
+        unsigned Threshold = allocatableRCRegs_[RC].count();
+        // Be conservative. If both sides are virtual registers, do not coalesce
+        // if this will cause a high use density interval to target a smaller
+        // set of registers.
+        if (SmallRegSize > Threshold || LargeRegSize > Threshold) {
+          LiveVariables::VarInfo &svi = lv_->getVarInfo(LargeReg);
+          LiveVariables::VarInfo &dvi = lv_->getVarInfo(SmallReg);
+          if ((float)dvi.NumUses / SmallRegSize <
+              (float)svi.NumUses / LargeRegSize) {
+            Again = true;  // May be possible to coalesce later.
+            return false;
+          }
         }
       }
     }
diff --git a/test/CodeGen/X86/2008-04-17-CoalescerBug.ll b/test/CodeGen/X86/2008-04-17-CoalescerBug.ll
new file mode 100644
index 0000000..cd7c29b
--- /dev/null
+++ b/test/CodeGen/X86/2008-04-17-CoalescerBug.ll
@@ -0,0 +1,171 @@
+; RUN: llvm-as < %s | llc -mtriple=i386-apple-darwin | grep xorl | grep {%e}
+; Make sure xorl operands are 32-bit registers.
+
+	%struct.tm = type { i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i8* }
+	%struct.wxDateTime = type { %struct.wxLongLong }
+	%"struct.wxDateTime::TimeZone" = type { i32 }
+	%struct.wxLongLong = type { i64 }
+	%struct.wxString = type { %struct.wxStringBase }
+	%struct.wxStringBase = type { i32* }
+@.str = external constant [27 x i32]		; <[27 x i32]*> [#uses=1]
+@.str4 = external constant [14 x i32]		; <[14 x i32]*> [#uses=1]
+@_ZZNK10wxDateTime5GetTmERKNS_8TimeZoneEE12__FUNCTION__ = external constant [6 x i8]		; <[6 x i8]*> [#uses=1]
+@.str33 = external constant [29 x i32]		; <[29 x i32]*> [#uses=1]
+@.str89 = external constant [5 x i32]		; <[5 x i32]*> [#uses=1]
+
+define void @_ZNK10wxDateTime6FormatEPKwRKNS_8TimeZoneE(%struct.wxString* noalias sret  %agg.result, %struct.wxDateTime* %this, i32* %format, %"struct.wxDateTime::TimeZone"* %tz) {
+entry:
+	br i1 false, label %bb116.i, label %bb115.critedge.i
+bb115.critedge.i:		; preds = %entry
+	ret void
+bb116.i:		; preds = %entry
+	br i1 false, label %bb52.i.i, label %bb3118
+bb3118:		; preds = %bb116.i
+	ret void
+bb52.i.i:		; preds = %bb116.i
+	br i1 false, label %bb142.i, label %bb115.critedge.i.i
+bb115.critedge.i.i:		; preds = %bb52.i.i
+	ret void
+bb142.i:		; preds = %bb52.i.i
+	br i1 false, label %bb161.i, label %bb182.i
+bb161.i:		; preds = %bb142.i
+	br label %bb3261
+bb182.i:		; preds = %bb142.i
+	ret void
+bb3261:		; preds = %bb7834, %bb161.i
+	%tmp3263 = load i32* null, align 4		; <i32> [#uses=1]
+	%tmp3264 = icmp eq i32 %tmp3263, 37		; <i1> [#uses=1]
+	br i1 %tmp3264, label %bb3306, label %bb3267
+bb3267:		; preds = %bb3261
+	ret void
+bb3306:		; preds = %bb3261
+	%tmp3310 = invoke %struct.wxStringBase* @_ZN12wxStringBaseaSEPKw( %struct.wxStringBase* null, i32* getelementptr ([5 x i32]* @.str89, i32 0, i32 0) )
+			to label %bb3314 unwind label %lpad		; <%struct.wxStringBase*> [#uses=0]
+bb3314:		; preds = %bb3306
+	%tmp3316 = load i32* null, align 4		; <i32> [#uses=1]
+	switch i32 %tmp3316, label %bb7595 [
+		 i32 0, label %bb7819
+		 i32 37, label %bb7806
+		 i32 66, label %bb3477
+		 i32 72, label %bb5334
+		 i32 73, label %bb5484
+		 i32 77, label %bb6118
+		 i32 83, label %bb6406
+		 i32 85, label %bb6556
+		 i32 87, label %bb6708
+		 i32 89, label %bb7308
+		 i32 98, label %bb3477
+		 i32 99, label %bb3626
+		 i32 100, label %bb5184
+		 i32 106, label %bb5657
+		 i32 108, label %bb5809
+		 i32 109, label %bb5968
+		 i32 119, label %bb6860
+		 i32 120, label %bb3626
+		 i32 121, label %bb7158
+	]
+bb3477:		; preds = %bb3314, %bb3314
+	ret void
+bb3626:		; preds = %bb3314, %bb3314
+	ret void
+bb5184:		; preds = %bb3314
+	ret void
+bb5334:		; preds = %bb3314
+	ret void
+bb5484:		; preds = %bb3314
+	ret void
+bb5657:		; preds = %bb3314
+	%tmp5661 = invoke i16 @_ZNK10wxDateTime12GetDayOfYearERKNS_8TimeZoneE( %struct.wxDateTime* %this, %"struct.wxDateTime::TimeZone"* %tz ) zeroext 
+			to label %invcont5660 unwind label %lpad		; <i16> [#uses=0]
+invcont5660:		; preds = %bb5657
+	ret void
+bb5809:		; preds = %bb3314
+	%tmp61.i.i8486 = icmp sgt i64 0, -1		; <i1> [#uses=1]
+	%tmp95.i.i8490 = icmp slt i64 0, 2147483647000		; <i1> [#uses=1]
+	%bothcond9308 = and i1 %tmp61.i.i8486, %tmp95.i.i8490		; <i1> [#uses=1]
+	br i1 %bothcond9308, label %bb91.i8504, label %bb115.critedge.i.i8492
+bb115.critedge.i.i8492:		; preds = %bb5809
+	ret void
+bb91.i8504:		; preds = %bb5809
+	br i1 false, label %bb155.i8541, label %bb182.i8560
+bb155.i8541:		; preds = %bb91.i8504
+	%tmp156.i85398700 = invoke %struct.tm* @gmtime_r( i32* null, %struct.tm* null )
+			to label %bb182.i8560 unwind label %lpad		; <%struct.tm*> [#uses=1]
+bb182.i8560:		; preds = %bb155.i8541, %bb91.i8504
+	%tm48.0.i8558 = phi %struct.tm* [ null, %bb91.i8504 ], [ %tmp156.i85398700, %bb155.i8541 ]		; <%struct.tm*> [#uses=0]
+	br i1 false, label %bb278.i8617, label %bb187.i8591
+bb187.i8591:		; preds = %bb182.i8560
+	%tmp245.i8588 = srem i64 0, 86400000		; <i64> [#uses=1]
+	br i1 false, label %bb264.i8592, label %bb265.i8606
+bb264.i8592:		; preds = %bb187.i8591
+	ret void
+bb265.i8606:		; preds = %bb187.i8591
+	%tmp268269.i8593 = trunc i64 %tmp245.i8588 to i32		; <i32> [#uses=1]
+	%tmp273.i8594 = srem i32 %tmp268269.i8593, 1000		; <i32> [#uses=1]
+	%tmp273274.i8595 = trunc i32 %tmp273.i8594 to i16		; <i16> [#uses=1]
+	br label %invcont5814
+bb278.i8617:		; preds = %bb182.i8560
+	%timeOnly50.0.i8622 = add i32 0, 0		; <i32> [#uses=1]
+	br i1 false, label %bb440.i8663, label %bb448.i8694
+bb440.i8663:		; preds = %bb278.i8617
+	invoke void @_Z10wxOnAssertPKwiPKcS0_S0_( i32* getelementptr ([27 x i32]* @.str, i32 0, i32 0), i32 1717, i8* getelementptr ([6 x i8]* @_ZZNK10wxDateTime5GetTmERKNS_8TimeZoneEE12__FUNCTION__, i32 0, i32 0), i32* getelementptr ([29 x i32]* @.str33, i32 0, i32 0), i32* getelementptr ([14 x i32]* @.str4, i32 0, i32 0) )
+			to label %bb448.i8694 unwind label %lpad
+bb448.i8694:		; preds = %bb440.i8663, %bb278.i8617
+	%tmp477.i8669 = srem i32 %timeOnly50.0.i8622, 1000		; <i32> [#uses=1]
+	%tmp477478.i8670 = trunc i32 %tmp477.i8669 to i16		; <i16> [#uses=1]
+	br label %invcont5814
+invcont5814:		; preds = %bb448.i8694, %bb265.i8606
+	%tmp812.0.0 = phi i16 [ %tmp477478.i8670, %bb448.i8694 ], [ %tmp273274.i8595, %bb265.i8606 ]		; <i16> [#uses=1]
+	%tmp58165817 = zext i16 %tmp812.0.0 to i32		; <i32> [#uses=1]
+	invoke void (%struct.wxString*, i32*, ...)* @_ZN8wxString6FormatEPKwz( %struct.wxString* noalias sret  null, i32* null, i32 %tmp58165817 )
+			to label %invcont5831 unwind label %lpad
+invcont5831:		; preds = %invcont5814
+	%tmp5862 = invoke i8 @_ZN12wxStringBase10ConcatSelfEmPKwm( %struct.wxStringBase* null, i32 0, i32* null, i32 0 ) zeroext 
+			to label %bb7834 unwind label %lpad8185		; <i8> [#uses=0]
+bb5968:		; preds = %bb3314
+	invoke void (%struct.wxString*, i32*, ...)* @_ZN8wxString6FormatEPKwz( %struct.wxString* noalias sret  null, i32* null, i32 0 )
+			to label %invcont5981 unwind label %lpad
+invcont5981:		; preds = %bb5968
+	ret void
+bb6118:		; preds = %bb3314
+	ret void
+bb6406:		; preds = %bb3314
+	ret void
+bb6556:		; preds = %bb3314
+	ret void
+bb6708:		; preds = %bb3314
+	ret void
+bb6860:		; preds = %bb3314
+	ret void
+bb7158:		; preds = %bb3314
+	ret void
+bb7308:		; preds = %bb3314
+	ret void
+bb7595:		; preds = %bb3314
+	ret void
+bb7806:		; preds = %bb3314
+	%tmp7814 = invoke %struct.wxStringBase* @_ZN12wxStringBase6appendEmw( %struct.wxStringBase* null, i32 1, i32 0 )
+			to label %bb7834 unwind label %lpad		; <%struct.wxStringBase*> [#uses=0]
+bb7819:		; preds = %bb3314
+	ret void
+bb7834:		; preds = %bb7806, %invcont5831
+	br label %bb3261
+lpad:		; preds = %bb7806, %bb5968, %invcont5814, %bb440.i8663, %bb155.i8541, %bb5657, %bb3306
+	ret void
+lpad8185:		; preds = %invcont5831
+	ret void
+}
+
+declare void @_Z10wxOnAssertPKwiPKcS0_S0_(i32*, i32, i8*, i32*, i32*)
+
+declare i8 @_ZN12wxStringBase10ConcatSelfEmPKwm(%struct.wxStringBase*, i32, i32*, i32) zeroext 
+
+declare %struct.tm* @gmtime_r(i32*, %struct.tm*)
+
+declare i16 @_ZNK10wxDateTime12GetDayOfYearERKNS_8TimeZoneE(%struct.wxDateTime*, %"struct.wxDateTime::TimeZone"*) zeroext 
+
+declare %struct.wxStringBase* @_ZN12wxStringBase6appendEmw(%struct.wxStringBase*, i32, i32)
+
+declare %struct.wxStringBase* @_ZN12wxStringBaseaSEPKw(%struct.wxStringBase*, i32*)
+
+declare void @_ZN8wxString6FormatEPKwz(%struct.wxString* noalias sret , i32*, ...)