diff options
| -rw-r--r-- | llvm/lib/Target/X86/X86InstrCompiler.td | 4 | ||||
| -rw-r--r-- | llvm/test/CodeGen/X86/i16lshr8pat.ll | 32 |
2 files changed, 36 insertions, 0 deletions
diff --git a/llvm/lib/Target/X86/X86InstrCompiler.td b/llvm/lib/Target/X86/X86InstrCompiler.td index 66326eaf50b..42235a497ce 100644 --- a/llvm/lib/Target/X86/X86InstrCompiler.td +++ b/llvm/lib/Target/X86/X86InstrCompiler.td @@ -1550,6 +1550,10 @@ def : Pat<(i8 (trunc (srl_su GR16:$src, (i8 8)))), (EXTRACT_SUBREG (i16 (COPY_TO_REGCLASS GR16:$src, GR16_ABCD)), sub_8bit_hi)>, Requires<[Not64BitMode]>; +def : Pat<(i8 (trunc (srl_su (i32 (anyext GR16:$src)), (i8 8)))), + (EXTRACT_SUBREG (i16 (COPY_TO_REGCLASS GR16:$src, GR16_ABCD)), + sub_8bit_hi)>, + Requires<[Not64BitMode]>; def : Pat<(i8 (trunc (srl_su GR32:$src, (i8 8)))), (EXTRACT_SUBREG (i32 (COPY_TO_REGCLASS GR32:$src, GR32_ABCD)), sub_8bit_hi)>, diff --git a/llvm/test/CodeGen/X86/i16lshr8pat.ll b/llvm/test/CodeGen/X86/i16lshr8pat.ll new file mode 100644 index 00000000000..7f2da8e2953 --- /dev/null +++ b/llvm/test/CodeGen/X86/i16lshr8pat.ll @@ -0,0 +1,32 @@ +; RUN: llc -march=x86 -stop-after expand-isel-pseudos <%s 2>&1 | FileCheck %s + +target datalayout = "e-m:e-p:32:32-f64:32:64-f80:32-n8:16:32-S128" +target triple = "i386-unknown-linux-gnu" + +; This test checks to make sure the lshr in %then1 block gets expanded using +; GR16_ABCD pattern rather than GR32_ABCD pattern. By using the 16-bit pattern +; this doesn't make the register liveness information look like the whole +; 32-bit register is a live value, and allows generally better live register +; analysis. +; CHECK-LABEL: bb.1.then1: +; CHECK-NOT: IMPLICIT_DEF +; CHECK-NOT: INSERT_SUBREG +; CHECK: sub_8bit_hi +; CHECK-LABEL: bb.2.endif1: + +define i16 @foo4(i32 %prec, i8 *%dst, i16 *%src) { +entry: + %cnd = icmp ne i32 %prec, 0 + %t0 = load i16, i16 *%src, align 2 + br i1 %cnd, label %then1, label %endif1 + +then1: + %shr = lshr i16 %t0, 8 + %conv = trunc i16 %shr to i8 + store i8 %conv, i8 *%dst, align 1 + br label %endif1 + +endif1: + %t2 = phi i16 [0, %then1], [%t0, %entry] + ret i16 %t2 +} |
