Shifter ops are not always free. Do not fold them (especially to form

complex load / store addressing mode) when they have higher cost and
when they have more than one use.

llvm-svn: 117509

1 files changed, 63 insertions, 9 deletions

diff --git a/llvm/test/CodeGen/ARM/shifter_operand.ll b/llvm/test/CodeGen/ARM/shifter_operand.ll
index 2bbe9fd2602..897fb1af01c 100644
--- a/llvm/test/CodeGen/ARM/shifter_operand.ll
+++ b/llvm/test/CodeGen/ARM/shifter_operand.ll
@@ -1,18 +1,72 @@
-; RUN: llc < %s -march=arm | grep add | grep lsl
-; RUN: llc < %s -march=arm | grep bic | grep asr
+; RUN: llc < %s -mtriple=armv7-apple-darwin -mcpu=cortex-a8 | FileCheck %s -check-prefix=A8
+; RUN: llc < %s -mtriple=armv7-apple-darwin -mcpu=cortex-a9 | FileCheck %s -check-prefix=A9
+; rdar://8576755
 
 
 define i32 @test1(i32 %X, i32 %Y, i8 %sh) {
-        %shift.upgrd.1 = zext i8 %sh to i32             ; <i32> [#uses=1]
-        %A = shl i32 %Y, %shift.upgrd.1         ; <i32> [#uses=1]
-        %B = add i32 %X, %A             ; <i32> [#uses=1]
+; A8: test1:
+; A8: add r0, r0, r1, lsl r2
+
+; A9: test1:
+; A9: add r0, r0, r1, lsl r2
+        %shift.upgrd.1 = zext i8 %sh to i32
+        %A = shl i32 %Y, %shift.upgrd.1
+        %B = add i32 %X, %A
         ret i32 %B
 }
 
 define i32 @test2(i32 %X, i32 %Y, i8 %sh) {
-        %shift.upgrd.2 = zext i8 %sh to i32             ; <i32> [#uses=1]
-        %A = ashr i32 %Y, %shift.upgrd.2                ; <i32> [#uses=1]
-        %B = xor i32 %A, -1             ; <i32> [#uses=1]
-        %C = and i32 %X, %B             ; <i32> [#uses=1]
+; A8: test2:
+; A8: bic r0, r0, r1, asr r2
+
+; A9: test2:
+; A9: bic r0, r0, r1, asr r2
+        %shift.upgrd.2 = zext i8 %sh to i32
+        %A = ashr i32 %Y, %shift.upgrd.2
+        %B = xor i32 %A, -1
+        %C = and i32 %X, %B
         ret i32 %C
 }
+
+define i32 @test3(i32 %base, i32 %base2, i32 %offset) {
+entry:
+; A8: test3:
+; A8: ldr r0, [r0, r2, lsl #2]
+; A8: ldr r1, [r1, r2, lsl #2]
+
+; lsl #2 is free
+; A9: test3:
+; A9: ldr r1, [r1, r2, lsl #2]
+; A9: ldr r0, [r0, r2, lsl #2]
+        %tmp1 = shl i32 %offset, 2
+        %tmp2 = add i32 %base, %tmp1
+        %tmp3 = inttoptr i32 %tmp2 to i32*
+        %tmp4 = add i32 %base2, %tmp1
+        %tmp5 = inttoptr i32 %tmp4 to i32*
+        %tmp6 = load i32* %tmp3
+        %tmp7 = load i32* %tmp5
+        %tmp8 = add i32 %tmp7, %tmp6
+        ret i32 %tmp8
+}
+
+declare i8* @malloc(...)
+
+define fastcc void @test4() nounwind {
+entry:
+; A8: test4:
+; A8: ldr r1, [r0, r0, lsl #2]
+; A8: str r1, [r0, r0, lsl #2]
+
+; A9: test4:
+; A9: add r0, r0, r0, lsl #2
+; A9: ldr r1, [r0]
+; A9: str r1, [r0]
+  %0 = tail call i8* (...)* @malloc(i32 undef) nounwind
+  %1 = bitcast i8* %0 to i32*
+  %2 = sext i16 undef to i32
+  %3 = getelementptr inbounds i32* %1, i32 %2
+  %4 = load i32* %3, align 4
+  %5 = add nsw i32 %4, 1
+  store i32 %5, i32* %3, align 4
+  ret void
+}