From 5a09690446a36f94f990db7d18d9b9ac8587888a Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Sun, 27 Apr 2008 00:37:18 +0000 Subject: Implement a signficant optimization for inline asm: When choosing between constraints with multiple options, like "ir", test to see if we can use the 'i' constraint and go with that if possible. This produces more optimal ASM in all cases (sparing a register and an instruction to load it), and fixes inline asm like this: void test () { asm volatile (" %c0 %1 " : : "imr" (42), "imr"(14)); } Previously we would dump "42" into a memory location (which is ok for the 'm' constraint) which would cause a problem because the 'c' modifier is not valid on memory operands. Isn't it great how inline asm turns 'missed optimization' into 'compile failed'?? Incidentally, this was the todo in PowerPC/2007-04-24-InlineAsm-I-Modifier.ll Please do NOT pull this into Tak. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50315 91177308-0d34-0410-b5e6-96231b3b80d8 --- test/CodeGen/X86/2008-04-26-Asm-Optimize-Imm.ll | 11 +++++++++++ 1 file changed, 11 insertions(+) create mode 100644 test/CodeGen/X86/2008-04-26-Asm-Optimize-Imm.ll (limited to 'test/CodeGen/X86/2008-04-26-Asm-Optimize-Imm.ll') diff --git a/test/CodeGen/X86/2008-04-26-Asm-Optimize-Imm.ll b/test/CodeGen/X86/2008-04-26-Asm-Optimize-Imm.ll new file mode 100644 index 0000000000..82721a53b8 --- /dev/null +++ b/test/CodeGen/X86/2008-04-26-Asm-Optimize-Imm.ll @@ -0,0 +1,11 @@ +; RUN: llvm-as < %s | llc | grep {1 \$2 3} +; rdar://5720231 +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" +target triple = "i386-apple-darwin8" + +define void @test() nounwind { +entry: + tail call void asm sideeffect " ${0:c} $1 ${2:c} ", "imr,imr,i,~{dirflag},~{fpsr},~{flags}"( i32 1, i32 2, i32 3 ) nounwind + ret void +} + -- cgit v1.2.3