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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.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@56381 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng
2008-09-20 01:28:05 +00:00
parent 4070e60efe
commit 5e8d9def77
2 changed files with 26 additions and 1 deletions
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5
lib/CodeGen/RegAllocLinearScan.cpp
View File

@ -855,9 +855,12 @@ void RALinScan::assignRegOrStackSlotAtInterval(LiveInterval* cur)
// All registers must have inf weight. Just grab one! // All registers must have inf weight. Just grab one!
minReg = BestPhysReg ? BestPhysReg : *RC->allocation_order_begin(*mf_); minReg = BestPhysReg ? BestPhysReg : *RC->allocation_order_begin(*mf_);
if (cur->weight == HUGE_VALF || if (cur->weight == HUGE_VALF ||
li_->getApproximateInstructionCount(*cur) == 0) li_->getApproximateInstructionCount(*cur) == 0) {
// Spill a physical register around defs and uses. // Spill a physical register around defs and uses.
li_->spillPhysRegAroundRegDefsUses(*cur, minReg, *vrm_); li_->spillPhysRegAroundRegDefsUses(*cur, minReg, *vrm_);
assignRegOrStackSlotAtInterval(cur);
return;
}
} }
// Find up to 3 registers to consider as spill candidates. // Find up to 3 registers to consider as spill candidates.

22
test/CodeGen/X86/2008-09-19-RegAllocBug.ll Normal file
View File

@ -0,0 +1,22 @@
; RUN: llvm-as < %s | llc -mtriple=i386-apple-darwin
; PR2808
@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
}