[PATCH] D52257: [Thumb1] Any imm of i8 type on Thumb1 should have cost of 1
Z. Zheng via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Mon Sep 24 09:17:08 PDT 2018
This revision was automatically updated to reflect the committed changes.
Closed by commit rL342898: [Thumb1] Any imm8 should have cost of 1 (authored by zzheng, committed by ).
Changed prior to commit:
https://reviews.llvm.org/D52257?vs=166570&id=166705#toc
Repository:
rL LLVM
https://reviews.llvm.org/D52257
Files:
llvm/trunk/lib/Target/ARM/ARMTargetTransformInfo.cpp
llvm/trunk/test/CodeGen/Thumb/consthoist-imm8-costs-1.ll
Index: llvm/trunk/test/CodeGen/Thumb/consthoist-imm8-costs-1.ll
===================================================================
--- llvm/trunk/test/CodeGen/Thumb/consthoist-imm8-costs-1.ll
+++ llvm/trunk/test/CodeGen/Thumb/consthoist-imm8-costs-1.ll
@@ -0,0 +1,39 @@
+; RUN: llc %s -o - | FileCheck %s
+
+target datalayout = "e-m:e-p:32:32-i64:64-v128:64:128-a:0:32-n32-S64"
+target triple = "thumbv6m-none-unknown-musleabi"
+
+ at a = global i8 undef, align 4
+
+; Check that store-merging generates a single str i32 rather than strb+strb+strh,
+; i.e., -1 is not moved by constant-hoisting.
+; CHECK: movs [[R1:r[0-9]+]], #255
+; CHECK: lsls [[R2:r[0-9]+]], [[R1]], #16
+; CHECK: str [[R2]]
+; CHECK: movs [[R3:r[0-9]+]], #255
+; CHECK: lsls [[R4:r[0-9]+]], [[R3]], #16
+; CHECK: str [[R4]]
+; CHECK-NOT: strh
+; CHECK-NOT: strb
+
+define void @ham() {
+bb:
+ br i1 undef, label %bb1, label %bb2
+
+bb1:
+ store i8 0, i8* getelementptr inbounds (i8, i8* @a, i32 1), align 1
+ store i8 0, i8* getelementptr inbounds (i8, i8* @a, i32 0), align 4
+ store i8 -1, i8* getelementptr inbounds (i8, i8* @a, i32 2), align 2
+ store i8 0, i8* getelementptr inbounds (i8, i8* @a, i32 3), align 1
+ br label %bb3
+
+bb2:
+ store i8 0, i8* getelementptr inbounds (i8, i8* @a, i32 9), align 1
+ store i8 0, i8* getelementptr inbounds (i8, i8* @a, i32 8), align 4
+ store i8 -1, i8* getelementptr inbounds (i8, i8* @a, i32 10), align 2
+ store i8 0, i8* getelementptr inbounds (i8, i8* @a, i32 11), align 1
+ br label %bb3
+
+bb3:
+ ret void
+}
Index: llvm/trunk/lib/Target/ARM/ARMTargetTransformInfo.cpp
===================================================================
--- llvm/trunk/lib/Target/ARM/ARMTargetTransformInfo.cpp
+++ llvm/trunk/lib/Target/ARM/ARMTargetTransformInfo.cpp
@@ -77,8 +77,8 @@
return 1;
return ST->hasV6T2Ops() ? 2 : 3;
}
- // Thumb1.
- if (SImmVal >= 0 && SImmVal < 256)
+ // Thumb1, any i8 imm cost 1.
+ if (Bits == 8 || (SImmVal >= 0 && SImmVal < 256))
return 1;
if ((~SImmVal < 256) || ARM_AM::isThumbImmShiftedVal(ZImmVal))
return 2;
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