diff --git a/test/CodeGen/Generic/2006-06-12-LowerSwitchCrash.ll b/test/CodeGen/Generic/2006-06-12-LowerSwitchCrash.ll
index b644bd2..47ee7c5 100644
--- a/test/CodeGen/Generic/2006-06-12-LowerSwitchCrash.ll
+++ b/test/CodeGen/Generic/2006-06-12-LowerSwitchCrash.ll
@@ -1,4 +1,4 @@
-; RUN: llvm-as < %s | llc -O0
+; RUN: llvm-as < %s | llc -fast
 
 define float @test(i32 %tmp12771278) {
         switch i32 %tmp12771278, label %bb1279 [
diff --git a/test/CodeGen/Generic/2006-06-13-ComputeMaskedBitsCrash.ll b/test/CodeGen/Generic/2006-06-13-ComputeMaskedBitsCrash.ll
index 1aa3c62..920cf3c 100644
--- a/test/CodeGen/Generic/2006-06-13-ComputeMaskedBitsCrash.ll
+++ b/test/CodeGen/Generic/2006-06-13-ComputeMaskedBitsCrash.ll
@@ -1,4 +1,4 @@
-; RUN: llvm-as < %s | llc -O0
+; RUN: llvm-as < %s | llc -fast
 	
 %struct.cl_perfunc_opts = type { i8, i8, i8, i8, i8, i8, i8, i8, i8, i8, i8, i8, i32, i32, i32, i32, i32, i32, i32 }
 @cl_pf_opts = external global %struct.cl_perfunc_opts		; <%struct.cl_perfunc_opts*> [#uses=2]
diff --git a/test/CodeGen/Generic/2007-04-13-SwitchLowerBadPhi.ll b/test/CodeGen/Generic/2007-04-13-SwitchLowerBadPhi.ll
index 1418bbf..b95a361 100644
--- a/test/CodeGen/Generic/2007-04-13-SwitchLowerBadPhi.ll
+++ b/test/CodeGen/Generic/2007-04-13-SwitchLowerBadPhi.ll
@@ -1,4 +1,4 @@
-; RUN: llvm-as < %s | llc -O0
+; RUN: llvm-as < %s | llc -fast
 ; PR 1323
 
 ; ModuleID = 'test.bc'
diff --git a/test/CodeGen/PowerPC/cr_spilling.ll b/test/CodeGen/PowerPC/cr_spilling.ll
index 4584c71..87315e0 100644
--- a/test/CodeGen/PowerPC/cr_spilling.ll
+++ b/test/CodeGen/PowerPC/cr_spilling.ll
@@ -1,4 +1,4 @@
-; RUN: llvm-as < %s | llc -march=ppc32 -regalloc=local -O0 -relocation-model=pic -o -
+; RUN: llvm-as < %s | llc -march=ppc32 -regalloc=local -fast -relocation-model=pic -o -
 ; PR1638
 
 @.str242 = external constant [3 x i8]		; <[3 x i8]*> [#uses=1]
diff --git a/test/CodeGen/X86/2008-04-15-LiveVariableBug.ll b/test/CodeGen/X86/2008-04-15-LiveVariableBug.ll
index 4bb8c6d..8cdff56 100644
--- a/test/CodeGen/X86/2008-04-15-LiveVariableBug.ll
+++ b/test/CodeGen/X86/2008-04-15-LiveVariableBug.ll
@@ -1,5 +1,5 @@
 ; RUN: llvm-as < %s | llc -mtriple=x86_64-apple-darwin
-; RUN: llvm-as < %s | llc -mtriple=x86_64-apple-darwin -relocation-model=pic -disable-fp-elim -O0 -regalloc=local
+; RUN: llvm-as < %s | llc -mtriple=x86_64-apple-darwin -relocation-model=pic -disable-fp-elim -fast -regalloc=local
 
 	%struct.CGPoint = type { double, double }
 	%struct.NSArray = type { %struct.NSObject }
diff --git a/test/CodeGen/X86/2008-05-21-CoalescerBug.ll b/test/CodeGen/X86/2008-05-21-CoalescerBug.ll
index 9ecd581..bed218f 100644
--- a/test/CodeGen/X86/2008-05-21-CoalescerBug.ll
+++ b/test/CodeGen/X86/2008-05-21-CoalescerBug.ll
@@ -1,4 +1,4 @@
-; RUN: llvm-as < %s | llc -march=x86 -O0 -fast-isel=false | grep mov | count 5
+; RUN: llvm-as < %s | llc -march=x86 -fast -fast-isel=false | grep mov | count 5
 ; PR2343
 
 	%llvm.dbg.anchor.type = type { i32, i32 }
diff --git a/test/CodeGen/X86/2009-03-23-LinearScanBug.ll b/test/CodeGen/X86/2009-03-23-LinearScanBug.ll
index b5298ae..0a4501e 100644
--- a/test/CodeGen/X86/2009-03-23-LinearScanBug.ll
+++ b/test/CodeGen/X86/2009-03-23-LinearScanBug.ll
@@ -1,4 +1,4 @@
-; RUN: llvm-as < %s | llc -mtriple=i386-apple-darwin -O0
+; RUN: llvm-as < %s | llc -mtriple=i386-apple-darwin -fast
 
 define fastcc void @optimize_bit_field() nounwind {
 bb4:
diff --git a/test/CodeGen/X86/2009-04-14-IllegalRegs.ll b/test/CodeGen/X86/2009-04-14-IllegalRegs.ll
index 0d66f69..5dda4e9 100644
--- a/test/CodeGen/X86/2009-04-14-IllegalRegs.ll
+++ b/test/CodeGen/X86/2009-04-14-IllegalRegs.ll
@@ -1,4 +1,4 @@
-; RUN: llvm-as < %s | llc -mtriple=i386-apple-darwin -O0 -regalloc=local | not grep sil
+; RUN: llvm-as < %s | llc -mtriple=i386-apple-darwin -fast -regalloc=local | not grep sil
 ; rdar://6787136
 
 	%struct.X = type { i8, [32 x i8] }
diff --git a/test/CodeGen/X86/add-with-overflow.ll b/test/CodeGen/X86/add-with-overflow.ll
index d015ceb..bfb86fd 100644
--- a/test/CodeGen/X86/add-with-overflow.ll
+++ b/test/CodeGen/X86/add-with-overflow.ll
@@ -1,7 +1,7 @@
 ; RUN: llvm-as < %s | llc -march=x86 | grep {jo} | count 2
 ; RUN: llvm-as < %s | llc -march=x86 | grep {jb} | count 2
-; RUN: llvm-as < %s | llc -march=x86 -O0 | grep {jo} | count 2
-; RUN: llvm-as < %s | llc -march=x86 -O0 | grep {jb} | count 2
+; RUN: llvm-as < %s | llc -march=x86 -fast | grep {jo} | count 2
+; RUN: llvm-as < %s | llc -march=x86 -fast | grep {jb} | count 2
 
 @ok = internal constant [4 x i8] c"%d\0A\00"
 @no = internal constant [4 x i8] c"no\0A\00"
diff --git a/test/CodeGen/X86/fast-isel-bail.ll b/test/CodeGen/X86/fast-isel-bail.ll
index fb4f37e..fa65d20 100644
--- a/test/CodeGen/X86/fast-isel-bail.ll
+++ b/test/CodeGen/X86/fast-isel-bail.ll
@@ -1,4 +1,4 @@
-; RUN: llvm-as < %s | llc -march=x86 -O0
+; RUN: llvm-as < %s | llc -march=x86 -fast
 
 ; This file is for regression tests for cases where FastISel needs
 ; to gracefully bail out and let SelectionDAGISel take over.
diff --git a/test/CodeGen/X86/fast-isel-gep-sext.ll b/test/CodeGen/X86/fast-isel-gep-sext.ll
index 4e988f5..ec420ff 100644
--- a/test/CodeGen/X86/fast-isel-gep-sext.ll
+++ b/test/CodeGen/X86/fast-isel-gep-sext.ll
@@ -1,5 +1,5 @@
-; RUN: llvm-as < %s | llc -march=x86-64 -O0 | grep movslq
-; RUN: llvm-as < %s | llc -march=x86 -O0
+; RUN: llvm-as < %s | llc -march=x86-64 -fast | grep movslq
+; RUN: llvm-as < %s | llc -march=x86 -fast
 ; PR3181
 
 ; GEP indices are interpreted as signed integers, so they
diff --git a/test/CodeGen/X86/fast-isel-shift-imm.ll b/test/CodeGen/X86/fast-isel-shift-imm.ll
index 7d8c9f5..c47b990 100644
--- a/test/CodeGen/X86/fast-isel-shift-imm.ll
+++ b/test/CodeGen/X86/fast-isel-shift-imm.ll
@@ -1,4 +1,4 @@
-; RUN: llvm-as < %s | llc -march=x86 -O0 | grep {sarl	\$80, %eax}
+; RUN: llvm-as < %s | llc -march=x86 -fast | grep {sarl	\$80, %eax}
 ; PR3242
 
 define i32 @foo(i32 %x) nounwind {
diff --git a/test/CodeGen/X86/pr1489.ll b/test/CodeGen/X86/pr1489.ll
index 10fa96a..a7f3e79 100644
--- a/test/CodeGen/X86/pr1489.ll
+++ b/test/CodeGen/X86/pr1489.ll
@@ -1,5 +1,5 @@
-; RUN: llvm-as < %s | llc -disable-fp-elim -O0 -mcpu=i486 | grep 1082126238 | count 3
-; RUN: llvm-as < %s | llc -disable-fp-elim -O0 -mcpu=i486 | grep 3058016715 | count 1
+; RUN: llvm-as < %s | llc -disable-fp-elim -fast -mcpu=i486 | grep 1082126238 | count 3
+; RUN: llvm-as < %s | llc -disable-fp-elim -fast -mcpu=i486 | grep 3058016715 | count 1
 ;; magic constants are 3.999f and half of 3.999
 ; ModuleID = '1489.c'
 target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64"
diff --git a/test/CodeGen/X86/volatile.ll b/test/CodeGen/X86/volatile.ll
index f919b5d..e40f87b 100644
--- a/test/CodeGen/X86/volatile.ll
+++ b/test/CodeGen/X86/volatile.ll
@@ -1,5 +1,5 @@
 ; RUN: llvm-as < %s | llc -march=x86 -mattr=sse2 | grep movsd | count 5
-; RUN: llvm-as < %s | llc -march=x86 -mattr=sse2 -O0 | grep movsd | count 5
+; RUN: llvm-as < %s | llc -march=x86 -mattr=sse2 -fast | grep movsd | count 5
 
 @x = external global double