[llvm-commits] [llvm] r56381 - in /llvm/trunk: lib/CodeGen/RegAllocLinearScan.cpp test/CodeGen/X86/2008-09-19-RegAllocBug.ll

[Evan Cheng]

Author: evancheng
Date: Fri Sep 19 20:28:05 2008
New Revision: 56381

URL: http://llvm.org/viewvc/llvm-project?rev=56381&view=rev
Log:
Fix PR2808. When regalloc runs out of register, it spill a physical register around the live interval being allocated. Do not continue to try to spill another register, just grab the physical register and move on.

Added:
    llvm/trunk/test/CodeGen/X86/2008-09-19-RegAllocBug.ll
Modified:
    llvm/trunk/lib/CodeGen/RegAllocLinearScan.cpp

Modified: llvm/trunk/lib/CodeGen/RegAllocLinearScan.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/RegAllocLinearScan.cpp?rev=56381&r1=56380&r2=56381&view=diff

==============================================================================
--- llvm/trunk/lib/CodeGen/RegAllocLinearScan.cpp (original)
+++ llvm/trunk/lib/CodeGen/RegAllocLinearScan.cpp Fri Sep 19 20:28:05 2008
@@ -855,9 +855,12 @@
     // All registers must have inf weight. Just grab one!
     minReg = BestPhysReg ? BestPhysReg : *RC->allocation_order_begin(*mf_);
     if (cur->weight == HUGE_VALF ||
-        li_->getApproximateInstructionCount(*cur) == 0)
+        li_->getApproximateInstructionCount(*cur) == 0) {
       // Spill a physical register around defs and uses.
       li_->spillPhysRegAroundRegDefsUses(*cur, minReg, *vrm_);
+      assignRegOrStackSlotAtInterval(cur);
+      return;
+    }
   }
 
   // Find up to 3 registers to consider as spill candidates.

Added: llvm/trunk/test/CodeGen/X86/2008-09-19-RegAllocBug.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/2008-09-19-RegAllocBug.ll?rev=56381&view=auto

==============================================================================
--- llvm/trunk/test/CodeGen/X86/2008-09-19-RegAllocBug.ll (added)
+++ llvm/trunk/test/CodeGen/X86/2008-09-19-RegAllocBug.ll Fri Sep 19 20:28:05 2008
@@ -0,0 +1,22 @@
+; RUN: llvm-as < %s | llc -mtriple=i386-apple-darwin
+; PR2808
+
+ at g_3 = external global i32		; <i32*> [#uses=1]
+
+define i32 @func_4() nounwind {
+entry:
+	%0 = load i32* @g_3, align 4		; <i32> [#uses=2]
+	%1 = trunc i32 %0 to i8		; <i8> [#uses=1]
+	%2 = sub i8 1, %1		; <i8> [#uses=1]
+	%3 = sext i8 %2 to i32		; <i32> [#uses=1]
+	%.0 = ashr i32 %3, select (i1 icmp ne (i8 zext (i1 icmp ugt (i32 ptrtoint (i32 ()* @func_4 to i32), i32 3) to i8), i8 0), i32 0, i32 ptrtoint (i32 ()* @func_4 to i32))		; <i32> [#uses=1]
+	%4 = urem i32 %0, %.0		; <i32> [#uses=1]
+	%5 = icmp eq i32 %4, 0		; <i1> [#uses=1]
+	br i1 %5, label %return, label %bb4
+
+bb4:		; preds = %entry
+	ret i32 undef
+
+return:		; preds = %entry
+	ret i32 undef
+}