Mercurial > hg > Members > tobaru > cbc > CbC_llvm
view test/CodeGen/ARM/2012-03-26-FoldImmBug.ll @ 33:e4204d083e25
LLVM 3.5
author | Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp> |
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date | Thu, 12 Dec 2013 14:32:10 +0900 |
parents | 95c75e76d11b |
children |
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; RUN: llc < %s -mtriple=thumbv7-apple-ios -mcpu=cortex-a8 | FileCheck %s ; ARM has a peephole optimization which looks for a def / use pair. The def ; produces a 32-bit immediate which is consumed by the use. It tries to ; fold the immediate by breaking it into two parts and fold them into the ; immmediate fields of two uses. e.g ; movw r2, #40885 ; movt r3, #46540 ; add r0, r0, r3 ; => ; add.w r0, r0, #3019898880 ; add.w r0, r0, #30146560 ; ; However, this transformation is incorrect if the user produces a flag. e.g. ; movw r2, #40885 ; movt r3, #46540 ; adds r0, r0, r3 ; => ; add.w r0, r0, #3019898880 ; adds.w r0, r0, #30146560 ; Note the adds.w may not set the carry flag even if the original sequence ; would. ; ; rdar://11116189 define i64 @t(i64 %aInput) nounwind { ; CHECK-LABEL: t: ; CHECK: movs [[REG:(r[0-9]+)]], #0 ; CHECK: movt [[REG]], #46540 ; CHECK: adds r{{[0-9]+}}, r{{[0-9]+}}, [[REG]] %1 = mul i64 %aInput, 1000000 %2 = add i64 %1, -7952618389194932224 ret i64 %2 }