diff mbox series

[05/16] cast: simplify [SZ]EXT + TRUNC to original size

Message ID 20180721211653.72853-6-luc.vanoostenryck@gmail.com (mailing list archive)
State Mainlined, archived
Headers show
Series casts simplification | expand

Commit Message

Luc Van Oostenryck July 21, 2018, 9:16 p.m. UTC 
An OP_ZEXT/OP_SEXT following by a OP_TRUNC to the original size is a NOP.

Simplify away such OP_TRUNC.

Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
---
 simplify.c                        | 10 ++++++++++
 validation/optim/ext-trunc-same.c |  1 -
 2 files changed, 10 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/simplify.c b/simplify.c
index 1ac000e52..2549860e3 100644
--- a/simplify.c
+++ b/simplify.c
@@ -1008,6 +1008,16 @@  static int simplify_cast(struct instruction *insn)
 			return replace_pseudo(insn, &insn->src1, def->src);
 		}
 		break;
+	case OP_ZEXT:
+	case OP_SEXT:
+		switch (insn->opcode) {
+		case OP_TRUNC:
+			osize = def->orig_type->bit_size;
+			if (size == osize)
+				return replace_with_pseudo(insn, def->src);
+			break;
+		}
+		break;
 	}
 
 	return 0;
diff --git a/validation/optim/ext-trunc-same.c b/validation/optim/ext-trunc-same.c
index 634fdb87a..2bfcf0304 100644
--- a/validation/optim/ext-trunc-same.c
+++ b/validation/optim/ext-trunc-same.c
@@ -11,7 +11,6 @@  short ueq(unsigned short x)
 /*
  * check-name: ext-trunc-same
  * check-command: test-linearize -Wno-decl $file
- * check-known-to-fail
  *
  * check-output-ignore
  * check-output-excludes: trunc\\.