[llvm-commits] [llvm] r82825 - in /llvm/trunk: lib/CodeGen/MachineLICM.cpp test/CodeGen/X86/sink-hoist.ll test/CodeGen/X86/sink.ll

[Dan Gohman]

Author: djg
Date: Fri Sep 25 18:58:45 2009
New Revision: 82825

URL: http://llvm.org/viewvc/llvm-project?rev=82825&view=rev
Log:
Unbreak MachineLICM for instructions that reference RIP on x86-64 too.

Added:
    llvm/trunk/test/CodeGen/X86/sink-hoist.ll
      - copied, changed from r82819, llvm/trunk/test/CodeGen/X86/sink.ll
Removed:
    llvm/trunk/test/CodeGen/X86/sink.ll
Modified:
    llvm/trunk/lib/CodeGen/MachineLICM.cpp

Modified: llvm/trunk/lib/CodeGen/MachineLICM.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/MachineLICM.cpp?rev=82825&r1=82824&r2=82825&view=diff

==============================================================================
--- llvm/trunk/lib/CodeGen/MachineLICM.cpp (original)
+++ llvm/trunk/lib/CodeGen/MachineLICM.cpp Fri Sep 25 18:58:45 2009
@@ -43,6 +43,7 @@
   class VISIBILITY_HIDDEN MachineLICM : public MachineFunctionPass {
     const TargetMachine   *TM;
     const TargetInstrInfo *TII;
+    const TargetRegisterInfo *TRI;
 
     // Various analyses that we use...
     MachineLoopInfo      *LI;      // Current MachineLoopInfo
@@ -135,6 +136,7 @@
   Changed = false;
   TM = &MF.getTarget();
   TII = TM->getInstrInfo();
+  TRI = TM->getRegisterInfo();
   RegInfo = &MF.getRegInfo();
 
   // Get our Loop information...
@@ -254,8 +256,25 @@
     if (Reg == 0) continue;
 
     // Don't hoist an instruction that uses or defines a physical register.
-    if (TargetRegisterInfo::isPhysicalRegister(Reg))
-      return false;
+    if (TargetRegisterInfo::isPhysicalRegister(Reg)) {
+      // If this is a physical register use, we can't move it.  If it is a def,
+      // we can move it, but only if the def is dead.
+      if (MO.isUse()) {
+        // If the physreg has no defs anywhere, it's just an ambient register
+        // and we can freely move its uses.
+        if (!RegInfo->def_empty(Reg))
+          return false;
+        // Check for a def among the register's aliases too.
+        for (const unsigned *Alias = TRI->getAliasSet(Reg); *Alias; ++Alias)
+          if (!RegInfo->def_empty(*Alias))
+            return false;
+        // Otherwise it's safe to move.
+        continue;
+      } else if (!MO.isDead()) {
+        // A def that isn't dead. We can't move it.
+        return false;
+      }
+    }
 
     if (!MO.isUse())
       continue;

Copied: llvm/trunk/test/CodeGen/X86/sink-hoist.ll (from r82819, llvm/trunk/test/CodeGen/X86/sink.ll)
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/sink-hoist.ll?p2=llvm/trunk/test/CodeGen/X86/sink-hoist.ll&p1=llvm/trunk/test/CodeGen/X86/sink.ll&r1=82819&r2=82825&rev=82825&view=diff

==============================================================================
--- llvm/trunk/test/CodeGen/X86/sink.ll (original)
+++ llvm/trunk/test/CodeGen/X86/sink-hoist.ll Fri Sep 25 18:58:45 2009
@@ -16,3 +16,27 @@
   %z = select i1 %c, double %a, double %b
   ret double %z
 }
+
+; Hoist floating-point constant-pool loads out of loops.
+
+; CHECK: bar:
+; CHECK: movsd
+; CHECK: align
+define void @bar(double* nocapture %p, i64 %n) nounwind {
+entry:
+  %0 = icmp sgt i64 %n, 0
+  br i1 %0, label %bb, label %return
+
+bb:
+  %i.03 = phi i64 [ 0, %entry ], [ %3, %bb ]
+  %scevgep = getelementptr double* %p, i64 %i.03
+  %1 = load double* %scevgep, align 8
+  %2 = fdiv double 3.200000e+00, %1
+  store double %2, double* %scevgep, align 8
+  %3 = add nsw i64 %i.03, 1
+  %exitcond = icmp eq i64 %3, %n
+  br i1 %exitcond, label %return, label %bb
+
+return:
+  ret void
+}

Removed: llvm/trunk/test/CodeGen/X86/sink.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/sink.ll?rev=82824&view=auto

==============================================================================
--- llvm/trunk/test/CodeGen/X86/sink.ll (original)
+++ llvm/trunk/test/CodeGen/X86/sink.ll (removed)
@@ -1,18 +0,0 @@
-; RUN: llc < %s -march=x86-64 -asm-verbose=false | FileCheck %s
-
-; Currently, floating-point selects are lowered to CFG triangles.
-; This means that one side of the select is always unconditionally
-; evaluated, however with MachineSink we can sink the other side so
-; that it's conditionally evaluated.
-
-; CHECK: foo:
-; CHECK-NEXT: divsd
-; CHECK-NEXT: testb $1, %dil
-; CHECK-NEXT: jne
-
-define double @foo(double %x, double %y, i1 %c) nounwind {
-  %a = fdiv double %x, 3.2
-  %b = fdiv double %y, 3.3
-  %z = select i1 %c, double %a, double %b
-  ret double %z
-}