From cdd8e46bec4e975d00a5abea808d8eb4138515c5 Mon Sep 17 00:00:00 2001 From: James Molloy Date: Wed, 19 Oct 2011 14:11:07 +0000 Subject: Use literal pool loads instead of MOVW/MOVT for materializing global addresses when optimizing for size. On spec/gcc, this caused a codesize improvement of ~1.9% for ARM mode and ~4.9% for Thumb(2) mode. This is codesize including literal pools. The pools themselves doubled in size for ARM mode and quintupled for Thumb mode, leaving suggestion that there is still perhaps redundancy in LLVM's use of constant pools that could be decreased by sharing entries. Fixes PR11087. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142530 91177308-0d34-0410-b5e6-96231b3b80d8 --- test/CodeGen/ARM/2011-10-18-DisableMovtSize.ll | 27 ++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) create mode 100644 test/CodeGen/ARM/2011-10-18-DisableMovtSize.ll (limited to 'test/CodeGen/ARM') diff --git a/test/CodeGen/ARM/2011-10-18-DisableMovtSize.ll b/test/CodeGen/ARM/2011-10-18-DisableMovtSize.ll new file mode 100644 index 0000000000..6dae75be91 --- /dev/null +++ b/test/CodeGen/ARM/2011-10-18-DisableMovtSize.ll @@ -0,0 +1,27 @@ +; RUN: llc < %s -mtriple=armv7-apple-darwin | FileCheck %s +; RUN: llc < %s -mtriple=armv7-unknown-linux-eabi | FileCheck %s + +; Check that when optimizing for size, a literal pool load is used +; instead of the (potentially faster) movw/movt pair when loading +; a large constant. + +@x = global i32* inttoptr (i32 305419888 to i32*), align 4 + +define i32 @f() optsize { + ; CHECK: f: + ; CHECK: ldr r{{.}}, {{.?}}LCPI{{.}}_{{.}} + ; CHECK: ldr r{{.}}, [{{(pc, )?}}r{{.}}] + ; CHECK: ldr r{{.}}, [r{{.}}] + %1 = load i32** @x, align 4 + %2 = load i32* %1 + ret i32 %2 +} + +define i32 @g() { + ; CHECK: g: + ; CHECK: movw + ; CHECK: movt + %1 = load i32** @x, align 4 + %2 = load i32* %1 + ret i32 %2 +} -- cgit v1.2.3-70-g09d2