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1. Make it fold blocks separated by an unconditional branch. This enables jump threading to see a broader scope. 2. Make jump threading able to eliminate locally redundant loads when they feed the branch condition of a block. This frequently occurs due to reg2mem running. 3. Make jump threading able to eliminate *partially redundant* loads when they feed the branch condition of a block. This is common in code with lots of loads and stores like C++ code and 255.vortex. This implements thread-loads.ll and rdar://6402033. Per the fixme's, several pieces of this should be moved into Transforms/Utils. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60148 91177308-0d34-0410-b5e6-96231b3b80d8
35 lines
1.0 KiB
LLVM
35 lines
1.0 KiB
LLVM
; RUN: llvm-as < %s | opt -jump-threading -mem2reg -simplifycfg | llvm-dis | grep {ret i32 1}
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; rdar://6402033
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; Test that we can thread through the block with the partially redundant load (%2).
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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-f80:128:128"
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target triple = "i386-apple-darwin7"
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define i32 @foo(i32* %P) nounwind {
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entry:
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%0 = tail call i32 (...)* @f1() nounwind ; <i32> [#uses=1]
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%1 = icmp eq i32 %0, 0 ; <i1> [#uses=1]
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br i1 %1, label %bb1, label %bb
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bb: ; preds = %entry
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store i32 42, i32* %P, align 4
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br label %bb1
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bb1: ; preds = %entry, %bb
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%res.0 = phi i32 [ 1, %bb ], [ 0, %entry ] ; <i32> [#uses=2]
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%2 = load i32* %P, align 4 ; <i32> [#uses=1]
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%3 = icmp sgt i32 %2, 36 ; <i1> [#uses=1]
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br i1 %3, label %bb3, label %bb2
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bb2: ; preds = %bb1
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%4 = tail call i32 (...)* @f2() nounwind ; <i32> [#uses=0]
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ret i32 %res.0
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bb3: ; preds = %bb1
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ret i32 %res.0
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}
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declare i32 @f1(...)
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declare i32 @f2(...)
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