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pr6480: Don't try producing ld/st-multiple instructions when the address is

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an undef value.  This is only going to come up for bugpoint-reduced tests --
correct programs will not access memory at undefined addresses -- so it's not
worth the effort of doing anything more aggressive.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97745 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Bob Wilson 2010-03-04 21:04:38 +00:00
parent d4076cfc83
commit bbf39b0fd9
2 changed files with 59 additions and 0 deletions
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5
lib/Target/ARM/ARMLoadStoreOptimizer.cpp
View File

@ -761,6 +761,11 @@ static bool isMemoryOp(const MachineInstr *MI) {
MI->getOperand(0).isUndef())
return false;
// Likewise don't mess with references to undefined addresses.
if (MI->getNumOperands() > 1 && MI->getOperand(1).isReg() &&
MI->getOperand(1).isUndef())
return false;
int Opcode = MI->getOpcode();
switch (Opcode) {
default: break;

54
test/CodeGen/ARM/2010-03-04-stm-undef-addr.ll Normal file
View File

@ -0,0 +1,54 @@
; RUN: llc < %s -march=arm
define void @"java.lang.String::getChars"([84 x i8]* %method, i32 %base_pc, [788 x i8]* %thread) {
%1 = sub i32 undef, 48 ; <i32> [#uses=1]
br i1 undef, label %stack_overflow, label %no_overflow
stack_overflow: ; preds = %0
unreachable
no_overflow: ; preds = %0
%frame = inttoptr i32 %1 to [17 x i32]* ; <[17 x i32]*> [#uses=4]
%2 = load i32* null ; <i32> [#uses=2]
%3 = getelementptr inbounds [17 x i32]* %frame, i32 0, i32 14 ; <i32*> [#uses=1]
%4 = load i32* %3 ; <i32> [#uses=2]
%5 = load [8 x i8]** undef ; <[8 x i8]*> [#uses=2]
br i1 undef, label %bci_13, label %bci_4
bci_13: ; preds = %no_overflow
br i1 undef, label %bci_30, label %bci_21
bci_30: ; preds = %bci_13
%6 = icmp sle i32 %2, %4 ; <i1> [#uses=1]
br i1 %6, label %bci_46, label %bci_35
bci_46: ; preds = %bci_30
store [84 x i8]* %method, [84 x i8]** undef
br i1 false, label %no_exception, label %exception
exception: ; preds = %bci_46
ret void
no_exception: ; preds = %bci_46
ret void
bci_35: ; preds = %bci_30
%7 = getelementptr inbounds [17 x i32]* %frame, i32 0, i32 15 ; <i32*> [#uses=1]
store i32 %2, i32* %7
%8 = getelementptr inbounds [17 x i32]* %frame, i32 0, i32 14 ; <i32*> [#uses=1]
store i32 %4, i32* %8
%9 = getelementptr inbounds [17 x i32]* %frame, i32 0, i32 13 ; <i32*> [#uses=1]
%10 = bitcast i32* %9 to [8 x i8]** ; <[8 x i8]**> [#uses=1]
store [8 x i8]* %5, [8 x i8]** %10
call void inttoptr (i32 13839116 to void ([788 x i8]*, i32)*)([788 x i8]* %thread, i32 7)
ret void
bci_21: ; preds = %bci_13
ret void
bci_4: ; preds = %no_overflow
store [8 x i8]* %5, [8 x i8]** undef
store i32 undef, i32* undef
call void inttoptr (i32 13839116 to void ([788 x i8]*, i32)*)([788 x i8]* %thread, i32 7)
ret void
}